California buckeye (Aesculus californica) at 2694 McAllister

SF's Most Famous Native Tree in Bloom

June 06, 2020 by Michael Sullivan

The California buckeye (Aesculus californica) at 2694 McAllister is one of San Francisco’s most notable trees, and it’s certainly the most famous of the trees that are native to San Francisco. It’s a huge specimen, and very old - so old that many think it existed before the turn of the century neighborhood around it. It’s in full bloom right now, with hundreds of the showy clusters of white flowers that the tree puts out in May and June every year. When I’m asked about my favorite trees in the City, this one is always at or near the top.

This tree has an interesting recent history. In 1999 the then-owner of the property posted plans to build a second home on the corner lot. The designs for the house placed it in a spot that would have required the removal of the tree. The City’s tree-lovers, led by environmentalist activist Beatrice Laws, responded with such a fierce outcry - hundreds of citizens signed petitions and letters to City Hall - that the property owner ultimately conceded. The plans were redrawn to move the home to a part of the lot where it would not damage the tree, and as part of the settlement, an easement was drawn up between the property owner and Friends of the Urban Forest (my law firm at the time wrote the easement as pro bono project for FUF) to permanently protect the tree. Under the easement, any removal or significant pruning to the tree requires FUF’s consent. At the time, it was the only street tree in the City protected by an easement (I’m told there is now a second).

Much later, in 2019, the tree was granted “landmark tree” status by the San Francisco Urban Forestry Council in a unanimous vote, granting it a second layer of protection.

California buckeyes can be found on wind-protected sites in the dry slopes and canyons of California’s coastal range and Sierra foothills. The leaves of the tree typically drop in July (an adaptation to our long, dry summers) unless summer water is provided. After the tree’s flowers fade, one or two pear-shaped fruits form on each flower cluster, and inside each fruit’s leathery jacket is a seed with a shiny brown coat. California’s native Americans knew the tree - they crushed the tree’s poisonous seeds and added them to dammed-up streams to stupefy fish, making them easy to catch. (Even today, you can find California buckeyes near old Indian campgrounds.)

San Francisco Magazine Story

June 03, 2020 by Michael Sullivan

A reader recently let me know that the link to the May 2017 article in San Francisco Magazine was broken. That article, written by Lynn Rapoport, is my favorite of all of the articles that have been written about San Francisco’s urban forest. It’s beautifully written, and the article comes the closest to explaining why I (and I think many of you) love the trees of this City so much. So I’m restoring it to the site in hopes that 2020 readers will enjoy it as much as those from three years ago:

Higher Education

Why I’m trying to learn the name of every tree species in San Francisco. By Lynn Rapoport

Sometime in the second half of 2016, I set out on a series of neighborhood walks with my friend Masha – like me, a fan of four-hour urban investigations, but, unlike me, possessed of a deep store of botanical knowledge. On these walks I learned the name of the jacaranda, the tree, it turned out, whose lavender blossoms had floated down over the proceedings at my best friend’s wedding a decade earlier. I saw my first Norfolk Island pine, outlandishly sculpted by evolution to resemble some crowing achievement of mid-century modern design. I found out that running one’s hand along the trunk of a flaxleaf paperbark tree is indeed like petting a stack of handmade loose-leaf. And I became acquainted with the ginkgo, contemporary of dinosaurs, the female seldom seen here owing to the puke-like tang of its fruit.

It felt strange to suddenly know these things, given that trees had previously presented as an agreeable peripheral blur while I wandered through the city that’s been my home for 23 years. It wasn’t that I didn’t care about nature, but I’d always been a pretty vague, generalist appreciator, whether walking out to the end of Tomales Point in Marin or traversing the hillside gardens flanking the staircases above the Castro. So it’s unclear why 2016 – an exciting time in all our lives – was the year I precipitously turned into someone who spends her weekends peering up at shaggy bark, catkins, and pinnately compound leaf arrangements, murmuring names like “shoestring acacia” and “mountain she-oak”.

Some share of the credit – or blame – resides with a man named Mike Sullivan, to whom Masha and I had developed a somewhat cult follower-like attachment. Onetime board president of Friends of the Urban Forest and keeper of the blog San Francisco Trees, Sullivan wrote the essential urban-forest guidebook The Trees of San Francisco, a compendium of walking tours and tree profiles that has taken us in search of European hornbeams in Potrero Hill, Port Orford cedars in the Panhandle, and Sydney golden wattles in Pacific Heights – where I also caught my first glimpse of the controversial Monterey cypress hedge enshrouding the Spreckels mansion, home to romance novelist Danielle Steel.

By the time we’d finished our debut tour and I’d seen my first gorgeous, willowy mayten and crushed between my fingers the deliciously fragrant leaves of my first California bay, I found it baffling that I could have been so unconcerned with the names, morphology and customs of an entire charismatic category of this planet’s living things. I resolved to get on a first-name basis with as many San Francisco representatives – 124,795 street trees encompassing some 500 species, per a city census completed in January – as I could find.

It sounds a bit compulsive, like some kind of taxonomic hoarding. But I think there’s more to it than just a drive to collect facts. When I met up with Sullivan in March, he pointed out that learning to identify San Francisco’s urban forest can also be an extension of the glorious perennial occupation of learning to know San Francisco itself. We were walking through Parnassus Heights, where Sullivan, a startup and venture capital lawyer by trade, lives with his husband, their son, and a dog named Mather (after the city-owned family camp in Yosemite). As we paused on Parnassus Avenue opposite a row of red flowering gums, one of the many antipodean species that love our foggy coastal climate, he talked about the “serendipitous” discoveries he’s made, arboreal and otherwise, walking around the city during his 33-year tenure here.

And these tree walks do feel like an outgrowth of two-plus decades of urban explorations that have rewarded me with a more densely annotated map of this city I adore. In the new year, waiting for the Bailey’s acacias to bloom, and then the Victorian boxes, and then the California buckeyes, it dawned on me that, contrary to conventional wisdom, San Francisco has seasons, erratic and overlapping though they may be. Even the fallen leaves of a towering silk oak that pile up outside the doorway of the hipster barbershop down the block from my house have somehow come to texture my understanding of this place.

That richness has activated something, too, a renewed ability to be curious and dazzled in a city where I’ve lately been more focused on a distressing housing market, on anxieties about how much longer, as a renter, I’ll be able to hang on here. Spending time staring up at the aerial root systems of New Zealand Christmas trees, or crumpling and smelling a bay laurel leaf like the ones I put in my stockpot, or learning to pick out the metallic sound of the Anna’s hummingbirds that frequent the bottlebrushes, I suppose I’m doubling down on my emotional stake in San Francisco, amid uncertainty, despite possible heartbreak ahead. Maybe there’s something consoling about keeping company with the city’s most permanent residents.

As Sullivan pointed out, many of them, far from their native soil, reflect the contradictory emergence, over the years, of a treescape unique to San Francisco, one that self-selects for thriving amid sandy soils, harsh winds, fog, seven or eight months without rain, and of course, cement. Noting that he could be dropped into a San Francisco stripped bare of any other identifying markers and know it by its trees, Sullivan said “We’ve almost created our own native urban forest here.” It was a remark unlikely to thrill the local purists who dream of ridding the city of invasive plants – a ship that has long since sailed out of San Francisco Bay. But I found the idea evocative, and after we’d said our goodbyes and I was walking home over the 17th Street hill, I realized that my map of the city, with its singular population of trees, had gained another new overlay. Wandering through Parnassus Heights a few weeks later on our own, Masha and I passed the 20-foot tall soapbark tree that Sullivan and his husband had planted outside their house the week in 2004 that their son was born. I was happy they’d been able to put down roots, and envious, too, because I hadn’t managed to do the same in this wondrous place with its inhospitable soil. That ship, too, had probably sailed. Or maybe it hadn’t. We continued walking through the urban forest, searching for unknown points on a map, eyes turned upward toward the branches.

Castro #covidtreetour (5-31-20)

June 02, 2020 by Michael Sullivan

One of the city’s best coast live oaks (Quercus agrifolia) at 19th and Noe — One of the city’s best coast live oaks (*Quercus agrifolia*) at 19th and Noe

This week’s San Francisco #covidtreetour, where we chalk tree descriptions and -> directional arrows -> on sidewalks, to allow social-distancing walkers to safely explore the urban forest, was in the Castro/Eureka Valley neighborhood. Our group is the same: Jason Dewees (author of Designing with Palms), Richard Turner (retired editor of Pacific Horticulture), and I’m Mike Sullivan, author of Trees of San Francisco.

This tour is concentrated in the eastern end of Eureka Valley, between 18th and 19th streets, in the blocks east of Castro Street. It begins at the Noe Hill Market, 19th and Noe, with a magnificent coast live oak, one of San Francisco’s few native tree species.

The walk heads east on 19th Street to Sanchez Street, then north on Sanchez to Hancock Street, east on Hancock to Church Street, returns west on Hancock to Noe Street, jogs south on Noe and then returns north on Noe to 18th Street, east on 18th to Sanchez, then west on 18th to Hartford Street, south on Hartford to 19th Street, and east on 19th to the tour’s beginning at Noe Street.

Follow these tours on instagram: #covidtreetour

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 59. White arrows on the pavement provide directions whenever a turn is needed.

19th Street, SW corner of Noe

1. 4001 - 18th Coast live oak (Quercus agrifolia), California native! And one of the few trees native to San Francisco (tree is on Noe)

19th Street, Noe to Sanchez, south side

2. 3995 - 19th Deodar cedar (Cedrus deodara), Himalayas

3. 3995 - 19th Mayten (Maytenus boaria), Chile

Mexican fan palm (Washingtonia robusta), with my masked cohorts Richard Turner (left) and Jason Dewees (right). — Mexican fan palm (*Washingtonia robusta*), with my masked cohorts Richard Turner (left) and Jason Dewees (right).

4. 3975 - 19th Mexican fan palm (Washingtonia robusta), Baja California, Mexico

5. 3959 - 19th New Zealand Christmas tree, pōhutukawa (Metrosideros excelsa), New Zealand

6. 3956 - 19th Western sycamore (Platanus racemosa), a California native, but rare on San Francisco streets (across the street)

7. 3957 - 19th Primrose tree (Lagunaria patersonii), Australia & S Pacific Islands

8. 3943 - 19th Yarwood plane tree or sycamore (Platanus ‘Yarwood’), originated at Sather Tower, UC Berkeley (these two trees are being pollarded; google the word to understand what that’s about)

9. 3931 - 19th Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA native (above wall on private propert.y). Turn left and head downhill on Sanchez

Sanchez Street, 19th to Hancock, west side

10. 590 Sanchez Ginkgo (Ginkgo biloba), China

11. 580 Sanchez Cajeput tree (Melaleuca quinquenervia), E Australia

12. 567 Sanchez Canary Island date palm (Phoenix canariensis), Canary Islands (across the street)

13. 526 Sanchez Wheel tree (Trochodendron aralioides), S Korea, Japan, Taiwan (the green plant at eye level between sidewalk and house). This is a very rare plant in San Francisco. Turn right on Hancock Street.

Hancock Street, Sanchez to Church, south side

14. 93 Hancock Eastern dogwood (Cornus florida ) E North America (note the one branch with variegated foliage — a sport or mutation)

15. 93 Hancock Victorian box (Pittosporum undulatum) E Australia (5 trees)

16. 93 Hancock Hinoki cypress (Chamaecyparis obtusa), Japan

Pin oak (Quercus palustris) - this tree is identifiable by its deeply lobed leaves — Pin oak (*Quercus palustris*) - this tree is identifiable by its deeply lobed leaves

17. 77 Hancock Purple-leaf plum (Prunus cerasifera), Eurasia (formerly SF’s most planted street tree)

18. 57 Hancock Red-flowering gum (Corymbia ficifolia), SW Australia

19. 55 Hancock Saucer magnolia (Magnolia x soulangeana), hybrid selection

20. 45 Hancock Pin oak (Quercus palustris), Midwest USA

21. 31-33 Hancock Queen palm (Syagrus romanzoffiana), Brazil (2 trees)

Please cross the street carefully here.

Hancock Street, Church to Sanchez, north side

22. 646 Church Evergreen pear (Pyrus kawakamii), Taiwan (tree is on Hancock)

little leaf linden (Tilia cordata) in bloom, with one of the plant’s yellowish-green “bracts” showing to the right of the flowers — little leaf linden (*Tilia cordata*) in bloom, with one of the plant’s yellowish-green “bracts” showing to the right of the flowers

23. 646 Church Little-leaf linden (Tilia cordata), Eurasia (tree is on Hancock)

24. 646 Church Brazilian pepper tree (Schinus terebinthifolius), Brazil

25. 20 Hancock Southern magnolia (Magnolia grandiflora), SE USA

26. 44 Hancock California buckeye (Aesculus californica ), San Francisco native tree!

27. 545 Sanchez Olive (Olea europaea), Mediterranean Basin (3 trees are on Hancock)

28. 545 Sanchez Strawberry tree (Arbutus unedo) SW Europe to Ireland (tree is on Hancock)

Hancock Street, Sanchez to Noe, north side

29. 112 Hancock Blackwood acacia (Acacia melanoxylon), SE Australia (3 trees)

30. 118 Hancock Ficus (Ficus microcarpa ‘Nitida’), India to China

31. 122 Hancock Brisbane box (Lophostemon confertus), E Australia (a fantastic specimen)

32. 132 Hancock Coast live oak (Quercus agrifolia), a California native - and one of the few trees native to San Francisco

Please cross the street carefully here

Hancock Street, Sanchez to Noe, south side

coast banksia (Banksia integrifolia) showing its "flower spike", an inflorescence made up of several hundred flowers densely packed around a woody axis — coast banksia (*Banksia integrifolia*) showing its "flower spike", an inflorescence made up of several hundred flowers densely packed around a woody axis

33. 135 Hancock Coast banksia (Banksia integrifolia), E Australia (above the wall, next to the garage

34. 135 Hancock Marjory Channon pittosporum (Pittosporum tenuifolium ‘Marjory Channon’), New Zealand

35. 137 Hancock Pygmy date palm (Phoenix roebelenii), S China, Laos, Vietnam

36. 183 Hancock Shoestring acacia (Acacia stenophylla), W Australia (above the fence)

37. 183 Hancock Zunca palm (Parajubaea sunkha), Bolivia (very rare in San Francisco - we need more of these!)

Turn uphill on Noe

Noe Street, south of Hancock, east side

38. 559 Noe Pomegranate (Punica granatum), W & Central Asia (a particularly fine specimen)

Backtrack - turn downhill on Noe

Noe Street, Hancock to 18th, east side

39. 549 Noe Cabbage tree or tī kōuka in Maori (Cordyline australis), New Zealand

Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia

40. 526 Noe Orange trees (Citrus sinensis), S Asia (across the street)

18th Street, Noe to Sanchez, south side

41. 3955 - 18th Lemon bottlebrush (Callistemon citrinus), E Australia

42. 3933 - 18th Brisbane box (Lophomyrtus confertus), E Australia

At Sanchez Street, cross 18th and backtrack on 18th - head back towards Noe on the north side of the street.

18th Street, Sanchez to Noe, north side

43. 3914 - 18th Callery pear (Pyrus calleryana), China (2 trees)

44. 3938 - 18th White champaca (Magnolia x alba), hybrid of SE Asian species (watch for the fragrant flowers)

45. 3946 - 18th Sweet michelia (Magnolia doltsopa), Himalayas

18th Street, Noe to Hartford, north side

a Melaleuca species - but not sure which one. This tree stumped all three of us!

46. 4000 - 18th Paperbark tree (Melaleuca sp.), Australia (tree is on Noe)

47. 4002 - 18th Loquat (Rhaphiolepis loquata, syn. Eriobotrya japonica), SE China (fruit is edible)

48. 4016 - 18th Weeping bottlebrush (Callistemon viminalis), E Australia. Turn left and head uphill on Hartford.

Hartford Street, 18th to 19th, east side

49. 115 Hartford Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia (tree was grafted at chest height)

50. 147 Hartford Bailey’s acacia (Acacia baileyana), E Australia (purple-leafed form)

148 Hartford Bailey’s acacia (Acacia baileyana), E Australia (green-leafed form, across the street)

51. 142 Hartford Peppermint willow (Agonis flexuosa), SW Australia (across the street)

52. 157 Hartford Gold medallion tree (Cassia leptophylla), Brazil

53. 167 Hartford Plum tree (Prunus x domestica), cultivated hybrid

54. 171 Hartford Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia (front tree)

Angel’s trumpet (Brugmansia ‘Charles Grimaldi’) — Angel’s trumpet (*Brugmansia* ‘Charles Grimaldi’)

Avocado tree (Persea americana), Mexico & Central America (tall tree behind the cherr at this address)

Dragon tree (Dracaena draco), Canary Islands (spiky plant behind the cherry)

55. 173 Hartford Angel’s trumpet (Brugmansia ‘Charles Grimaldi’), hybrid of South American species, named for the late San Francisco garden designer)

56. 187 Hartford Weeping bottlebrush (Callistemon viminalis), E Australia (3 trees). Turn left at 19th Street.

19th Street, Hartford to Noe, north side

57. 193 Noe Freeman maple (Acer x freemanii), hybrid of Acer rubrum & Acer saccharinum, both from E North America (tree is on 19th)

58. 4025 - 19th Victorian box (Pittosporum undulatum) E Australia (across the street; white flowers are strongly fragrant)

59. 4002 - 19th Chinese elm (Ulmus parvifolia), E Asia

There are a couple more interesting trees that we didn’t include on the tour - if you walk uphill on Noe from 19th to the corner of Cumberland (on the left side as you ascend, you’ll see two very large trees in the sidewalk just past Cumberland. These are swamp mahoganies (Eucalyptus robusta) - a rare tree in San Francisco, and we think these are the largest specimens in the City.

This walking tour of was organized by Mike Sullivan, author of The Trees of San Francisco (if you like this tour, there are 12 more neighborhood tree tours in Mike’s book), Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; and Richard Turner, retired editor of Pacific Horticulture magazine and editor of Trees of Golden Gate Park. If you’re a tree enthusiast, buy all three books! You can follow Mike (@sftreeguy) and Jason (@loulufan) on Instagram.

Russian Hill #covidtreetour (5-24-20)

May 25, 2020 by Michael Sullivan

[NOTE: our newest tour is of the Castro - chalked on 5/31 - that tour will be up on this site in a day or two!]

This week’s San Francisco #covidtreetour, where we chalk tree descriptions and -> directional arrows -> on sidewalks, to allow social-distancing walkers to safely explore the urban forest, was on Russian Hill. Our group is the same: Jason Dewees (author of Designing with Palms), Richard Turner (Editor Emeritus of Pacific Horticulture), and I’m Mike Sullivan, author of Trees of San Francisco. We saw some great trees today - one of the City’s biggest giant sequoias (see #23 below), and we found a “City Champion” - the largest of its kind in San Francisco (see #42 below).

This tour starts at the venerable Swensen’s Ice Cream Store, at the SW corner of Hyde and Union streets. The walk heads south on Hyde Street to Vallejo Street, then east on Vallejo to Jones Street, north on Jones to Green Street, west on Green to Leavenworth Street, north on Leavenworth to Union Street, a short jog east on Union and back to Leavenworth, continues north on Leavenworth to Filbert Street, west up the steps on Filbert to Hyde, then return south on Hyde to the tour’s beginning at Union Street.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 43. White arrows on the pavement provide directions whenever a turn is needed.

Ficus tree (Ficus microcarpa) on Hyde Street next to Swensen’s — Ficus tree (*Ficus microcarpa*) on Hyde Street next to Swensen’s

The street addresses provided below will help when the chalk has faded. Most of the trees are planted in sidewalk cut; a few are planted on private property between the sidewalk and the house; and some are planted in a mini-park on Hyde and in the quiet residential Havens Street.

Note: Swensen’s is, sadly, closed due to the pandemic. In an emergency, ice cream in containers is available at nearby markets.

Hyde Street, Union to Green, west side

1. 1999 Hyde Ficus tree (Ficus microcarpa ‘Nitida’), India to China

2. 1987 Hyde Cork oak (Quercus suber), Spain & Portugal (4 young trees)

3. 1901 Hyde London plane tree (Platanus x acerifolia), hybrid of E USA species and European species (tree is on Green Street)

Hyde Street, Green to Vallejo, west side

Mediterranean fan palms (Chamaerops humilis), emerging from the fence at 1834 Hyde (there are five more of the palms above the garage to the left) — Mediterranean fan palms (*Chamaerops humilis*), emerging from the fence at 1834 Hyde (there are five more of the palms above the garage to the left)

4. 1834 Hyde Mediterranean fan palms (Chamaerops humilis), western Mediterranean Basin (on left, above stone garage across the street; one is also emerging from the fence to the left of the door)

5. 1834 Hyde Queen palm (Syagrus romanzoffiana), Brazil (tallest palm, above stone garage across the street)

6. 1827 Hyde Fern pine (Afrocarpus gracilior), E Africa (several trees within Hyde & Vallejo Mini-park, on the left of the address). Turn left on Vallejo Street.

Vallejo Street, Hyde to Leavenworth, south side

7. 1255 Vallejo Glossy privet (Ligustrum lucidum), E Asia

8. 1255 Vallejo Southern magnolia (Magnolia grandiflora), SE USA

Vallejo Street, Leavenworth to Jones, south side

9. 1760 Leavenworth Ginkgo (Ginkgo biloba), China (2 trees are on Vallejo side of building)

10. 1187 Vallejo Blackwood acacia (Acacia melanoxylon), SE Australia

11. 1173 Vallejo Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia

12. 1140 Vallejo Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species, first discovered in San Francisco (tree is across the street)

13. 1120 Vallejo Brazilian pepper tree (Schinus terebinthifolius), Brazil (tree is across the street)

Jones Street, Vallejo to Green, west side

14. Vallejo & Jones Coast live oak (Quercus agrifolia), California native - and one of the few trees native to San Francisco (tree is above the Jones St wall, opposite 1085 Vallejo at the NE corner of Vallejo & Jones). Turn left on Jones Street.

A row of tulip trees (Liriodendron tulipifera) on Jones Street — A row of tulip trees (*Liriodendron tulipifera*) on Jones Street

15. 1827 Jones Tulip tree (Liriodendron tulipifera), E North America (look up to see the green and orange flowers; tallest hardwood tree in North America)

16. 999 Green Kapuka (Griselinia littoralis), New Zealand (tall hedge on Jones Street side of the high-rise tower)

17. 999 Green Hollywood juniper (Juniperus chinensis ‘Torulosa’), E Asia (SE corner of Green & Jones, next to kapuka hedge). Turn left at Green Street.

Green Street, Jones to Leavenworth, south side

18. 1025 Green Irish yew (Taxus baccata ‘Fastigiata’), Eurasia & N Africa (2 columnar trees against the house)

19. 1020 Green Evergreen dogwood (Cornus capitata), Himalayas (tree with big white flowers, across the street)

20. 1033 Green New Zealand Christmas tree, pōhutukawa (Metrosideros excelsa), New Zealand

21. 1033 Green King palms (Archontophoenix cunninghamiana), E Australia (2 young palms)

22. 1045 Green Washington thorn (Crataegus phaenopyrum) E USA

23. 1055 Green Giant sequoia (Sequoidendron giganteum), Sierra Nevada, CA native (largest tree species in the world; this tree is one of SF’s best examples)

24 1055 Green English holly (Ilex aquifolium), W Europe & N Africa

25. 1067 Green Lombardy poplar (Populus nigra ‘Italica’), a variety of Eurasian species (row of narrow trees along east side of 1097 Green)

26. 1097 Green Italian buckthorn (Rhamnus alaternus), Mediterranean Basin. Turn right and head downhill on Leavenworth.

Leavenworth Street, Green to Union, east side

27. 1900 Leavenworth Karo (Pittosporum crassifolium), New Zealand

28. 1932 Leavenworth Purple-leaf plum (Prunus cerasifera), Eurasia (formerly SF’s most planted street tree). Cross the street at Union, and turn right (downhill - the tour goes halfway down this block, and then backtracks.

Union Street, Leavenworth to Black Pl, north side

29. 1048 Union Two palms within the front courtyard:

Clara palm (Brahea armata ‘Clara’), Sonora, Mexico (taller palm on the right)

Mexican blue palm (Brahea armata), Baja California (on the left - it’s only visible if you take a couple steps down the stairs)

30. 1048 Union Apricot (Prunus armeniaca), C Asia

31. 1048 Union Fuyu persimmon (Diospyros kaki ‘Fuyu’), Japan

Return to Leavenworth Street, and turn right (downhill)

Leavenworth Street, Union to Filbert, west side

a Canary Island date palm (Phoenix canariensis) at the bottom of Havens Street — a Canary Island date palm (*Phoenix canariensis*) at the bottom of Havens Street

32. Havens Street Canary Island date palm (Phoenix canariensis), Canary Islands the palm is visible from the bottom of the steps). Havens Street is the street where Armistead Maupin, author of Tales of the City, lived while writing the book. It’s a dead end street, but it makes a lovely detour if you have extra time (we did not identify any trees on Havens other than the Canary Island palm).

33. 2049 Leavenworth Victorian box (Pittosporum undulatum) E Australia (also the entire block of trees on the opposite side of the street). Cross Filbert Street, turn left and head uphill on Filbert (one of San Francisco’s steepest streets - it’s a workout).

Filbert Street, Leavenworth to Hyde, north side

34. 1100 Filbert Firethorn (Pyracantha), Eurasia

35. 1110 Filbert Japanese maple (Acer palmatum), Korea & Japan

36. 1110 Filbert Flowering plum (Prunus sp.), Eurasia (fruit are ripening now)

37. 1110 Filbert Red-flowering gum (Corymbia ficifolia), SW Australia (corner of the garden)

38. 1126 Filbert Windmill palm (Trachycarpus fortunei), China

39. 1141 Filbert Monterey cypress (Hesperocyparis macrocarpa), from central California near Carmel (tallest conifer across the street)

40. 1150 Filbert Lemon bottlebrush (Callistemon citrinus), E Australia

41. 1198 Filbert Indian laurel fig (Ficus microcarpa), India to China (also across the street). At the top of Filbert, cross the street and turn left on Hyde.

Hyde Street, Filbert to Union, west side

42. 2051 Hyde Carisco (Persea indica), Madeira, Azores, Canary Islands. A close relative of the avocado tree, this is a rare tree in San Francisco. There are two trees here - I think the taller one is San Francisco’s “City Champion” for this species.

43. 2027 Hyde Brisbane box (Lophostemon confertus), E Australia

This walking tour of Russian Hill’s street trees was organized by Mike Sullivan, author of The Trees of San Francisco (if you like this Russian Hill tour, there are 12 more neighborhood tree tours in Mike’s book), Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; and Richard Turner, retired editor of Pacific Horticulture magazine and editor of Trees of Golden Gate Park. If you’re a tree enthusiast, buy all three books! You can follow Mike (@sftreeguy) and Jason (@loulufan) on Instagram.

Inner Mission Social Distancing Tree Tour (5-16-20)

May 18, 2020 by Michael Sullivan

Another Saturday, another San Francisco #covidtreetour, where we chalk tree descriptions and -> directional arrows -> on sidewalks, to allow social-distancing walkers to safely explore the urban forest. Our group is the same: Jason Dewees (author of Designing with Palms), Richard Turner (Editor Emeritus of Pacific Horticulture), and me. This week (Saturday, 5-16-20), we chalked the Inner Mission neighborhood - the tour is bounded by 16th, Valencia, 19th, and Dolores. It begins at the California State Historical Marker, which notes the first location of Mission Dolores Chapel on Albion Street at its intersection with Camp Street. (And a big thank you to Richard Turner, who types up these notes.)

Most trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in red, run from 1 to 53.

This walk heads south on Albion Street to 17th Street, then west on 17th to Valencia, south on Valencia to 18th, east on 18th, south on Lexington, west on 19th, north on Dolores, east on 17th, north on Guerrero, east on Camp, north on the west side of Albion to 16th, and back south on the east side of Albion to the tour’s beginning at Camp.

White arrows on the pavement provide directions whenever a turn is needed. The street numbers provided below will help when the chalk has faded. Most of the trees are planted in pockets in the sidewalk pavement; a few are planted on private property between the sidewalk and the house; and some are planted in the medians of Dolores and Guerrero and in Dolores Park.

Note: We knew we were taking a chance chalking this tour, given the forecast of rain. The rain did come, and most of the white chalk was washed away; the red chalked numbers, for the most part, remain. The trees, however, are still there, and this detailed itinerary will allow you to find them with ease.

Albion Street, Camp to 17th, east side

1. 145 Albion Water gum (Tristaniopsis laurina), E Australia

2. 145 Albion Queen palm (Syagrus romanzoffiana), Brazil

3. 157 Albion Lemon bottlebrush (Callistemon citrinus), E Australia f(in full bloom now)

152 Albion Weeping bottlebrush (Callistemon viminalis), E Australia (across the street; also in full bloom - interesting to see the two related species so close together)

4. 165 Albion Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species, first discovered in San Francisco

5. 168 Albion Snow-in-summer tree (Melaleuca linariifolia), E Australia (across the street)

6. 175 Albion Prickly paperbark (Melaleuca styphelioides), E Australia (across the street)

17th Street, Albion to Valencia, north side

7. 3412 - 17th New Zealand Christmas tree, called “pōhutukawa” in the Maori language (Metrosideros excelsa), New Zealand

Valencia Street, 17th to 18th, west side

8. 630 Valencia Brisbane box (Lophostemon confertus), E Australia

9. 630 Valencia Valley oak (Quercus lobata), California native (west end of building, inside the fence)

10. 600 block London plane tree (Platanus x acerifolia), hybrid of E USA species and European species (most of the trees on the east side of street)

11. 696 Valencia Silk oak (Grevillea robusta), E Australia (best specimen in SF; flowering at the top)

Cross 18th and turn left, crossing Valencia and continue one short block to Lexington, where you will turn right.

Lexington Street, 18th to 19th, east side

12. 103 Lexington Sweetshade (Hymenosporum flavum), E Australia

sweetshade tree (Hymenosporum flavum) — sweetshade tree (*Hymenosporum flavum*)

12 ½. 120 Lexington Japanese blueberry tree (Elaeocarpus decipiens), Japan (across the street)

13. 133 Lexington Primrose tree (Lagunaria pattersonii), Australia & S Pacific Islands

14. 153 Lexington Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia

150 Lexington Evergreen pear (Pyrus kawakamii), Taiwan (across the street)

15. 171 Lexington Bracelet honey myrtle (Melaleuca armillaris), SE Australia

16. 185 Lexington Elegant water gum (Tristaniopsis laurina ‘Elegant’), E Australia. Turn right on 19th Street.

19th Street, Lexington to Valencia, south side

17. 3471 - 19th Southern magnolia (Magnolia grandiflora), SE USA

19th Street, Valencia to Guerrero, south side

18. 3505 - 19th Chinaberry (Melia azederach), China & N India (rare in SF; a weed elsewhere)

19. 3505 - 19th Chinese pistache (Pistacia chinensis), W & C China (west end of building)

20. 3523 - 19th Glossy privet (Ligustrum lucidum), S China

21. 3528 - 19th Indian laurel fig (Ficus microcarpa), S Asia

22. Mission Pool Ginkgo (Ginkgo biloba), China (small tree in the sidewalk)

23. Mission Pool Spotted gum (Corymbia maculata), E Australia (the very large tree against the building - this is a spectacular specimen of this species, one of the best in SF)

24. 3573 - 19th Mimosa (Albizia julibrissin), Iran

19th Street, Guerrero to Dolores, south side

25. 3615 - 19th Fern-leaf Catalina ironwood (Lyonothamnus floribundus ssp. asplenifolius), Santa Cruz Island, CA native

26. 3623 - 19th Purple-leaf plum (Prunus cerasifera), Eurasia (formerly SF’s most planted street tree)

27. 3627 - 19th Sweetgum (Liquidambar styraciflua), E USA to Mexico & C America

28. 3635 - 19th Victorian box (Pittosporum undulatum) E Australia

29. 3665 - 19th Bronze loquat (Raphiolepis deflexa), E Asia

30. 3673 - 19th River wattle (Acacia cognata), SE Australia

31. 595 Dolores Silver dollar gum (Eucalyptus polyanthemos), E Australia (3 trees on 19th, north side)

Dolores Park

Turn right on Dolores, but first look across the street to the four palms that flank the 19th Street entrance to Dolores Park.

32. 19th St entrance Chilean palm (Jubaea chilensis), Chile (4 trees flanking the park entrance)

Dolores Street, 19th to 18th, east side

33. 591 Dolores Chilean pepper (Schinus polygamus), Chile (very rare in SF)

Canary Island palm (Phoenix canariensis) — Canary Island palm (*Phoenix canariensis*)

34. 583 Dolores Canary Island date palm (Phoenix canariensis), Canary Islands (also the dominant palm in the Dolores median)

35. 573 Dolores Red horse chestnut (Aesculus x carnea), hybrid of European and American species

36. 569 Dolores Southern magnolia (Magnolia grandiflora), SE USA

37. 561 Dolores Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia

38. 553 Dolores Turkish sweetgum (Liquidambar orientalis), E Mediterranean Basin

38 ½. 547 Dolores Mexican fan palm (Washingtonia robusta), Mexico (tall palm in the median)

39. 547 Dolores Blackwood acacia (Acacia melanoxylon), SE Australia

40. 527 Dolores Guadalupe palm (Brahea edulis), Guadalupe Island, Baja (short palm in the median)

Dolores Street, 18th to 17th, east side

41. 497 Dolores Carob (Ceratonia siliqua), Mediterranean Basin

42. 443 Dolores Brazilian pepper tree (Schinus terebinthifolius), Brazil

43. 431 Dolores Ficus (Ficus microcarpa), India to China. Turn right on 17th Street

17th Street, Dolores to Guerrero, south side

44. 3573 - 17th Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia

45. 3559 - 17th Cajeput tree (Melaleuca quinquenervia), E Australia

46. 3537 - 17th Red-flowering gum (Corymbia ficifolia), SW Australia

47. 3525 - 17th Carrotwood (Cupaniopsis anacardioides), E Australia. Cross Guerrero, and turn left on to head north on Guerrero.

Guerrero Street at 17th, west side

48. 490 Guerrero Australian willow (Geijera parviflora), E & SE Australia

Guerrero Street, 17th to Camp, east side

49. 451 Guerrero Shoestring acacia (Acacia stenophylla), W Australia (trees are in the median)

50. (Skipped)

Turn right and head east on Camp Street to Albion, where you will turn left.

Albion Street, Camp to 16th, west side

51. 144 Albion Snow-in-summer tree (Melaleuca linariifolia), E Australia. At 16th Street, cross Albion and head back on the south side of the street.

snow in summer (Melaleuca linariifolia) — snow in summer (*Melaleuca linariifolia*)

Albion Street, 16th to Camp, east side

52. 3139 16th Lemonwood (Pittosporum eugenioides), New Zealand

53. 131 Albion Cedro blanco (Cedrela fissilis), Argentina to Costa Rica (only one in SF)

Potrero Hill Social Distancing Tree Tour #covidtreetour (5-9-20)

May 12, 2020 by Michael Sullivan

We’re now into our 5th week of creating temporary “tree tours” in San Francisco neighborhoods by chalking tree descriptions and -> directional arrows -> on sidewalks. As regular readers know, these tours are made by Jason Dewees (author of Designing with Palms), Richard Turner (Editor Emeritus of Pacific Horticulture), and me. Today (Saturday, 5-16-20), we chalked the Mission neighborhood (that tour will be here in a day or two). Last Saturday (5-9-20), we were in the Potrero Hill neighborhood, and discovered an amazing diversity of really interesting and many rare trees - our best haul so far, I think. Sadly, a couple of days later, we faced the enemy of sidewalk chalk - rain! So if the chalk has faded, the info below will let you follow the tour, and check out a slice of Potrero Hill’s urban forest.

This tour begins with some uncommon trees just north of the northeast corner of Missouri and 19th streets, on the north slope of Potrero Hill. Most trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in red, run from 1 to 56.

The walk heads east on 19th Street to Texas, crosses the street, then continues west on 19th to Carolina, south on Carolina, up the Jack Balastreri Way steps, and continues up Carolina, crosses the street, then heads back down Carolina to 20th, east on 20th to Missouri, and north on Missouri to 19th, diagonally across the intersection from the start of the tour.

Note: Some of us plant geeks have difficulty with simple arithmetic, so you may notice that occasional numbers have been repeated and others left out. We’re working on it.

Missouri Street, north of 19th, east side

1. 391 Missouri Cajeput tree (Melaleuca quinquenervia), E Australia (large tree at this address)

2. 391 Missouri Cabbage tree (Cussonia spicata), S Africa (in yard). From here, head east on 19th.

19th Street, Missouri to Texas, north side

3. 1342 - 19th Strawberry tree (Arbutus unedo), Mediterranean basin & southwest Ireland

4. 398 Texas Victorian box (Pittosporum undulatum), E Australia (tree is on 19th)

5. 398 Texas Ovens wattle (Acacia pravissima), E Australia (tree is on 19th). At Texas, cross the 19th and head back east on the south side of the street.

19th Street, Texas to Missouri, south side

Jason Dewees (left), Mike Sullivan (center, with chalk) and Richard Turner (right) with a purple smoke tree (Cotinus coggygria ‘Royal Purple’)

6. 1301 - 19th Purple smoke tree (Cotinus coggygria ‘Royal Purple’), Eurasia. Cross Missouri, and look left for the next two trees - but the tour continues downhill/east on 19th.

Goat Hall, 19th & Missouri, SW corner

7. 400 Missouri Prickly paperbark (Melaleuca styphelioides), E Australia

8. 400 Missouri Karo (Pittosporum crassifolium), New Zealand

a row of weeping bottlebrush (Callistemon viminalis)

9. 400 Missouri Red-flowering gum (Corymbia ficifolia), SW Australia (tree is on 19th)

19th Street, Missouri to Connecticut, south side

10. St Teresa Church Weeping bottlebrush (Callistemon viminalis), E Australia (the trees line the entire block - trees are across the street on south side)

11. 401 Connecticut California buckeye (Aesculus californica), Bay Area native (tree is on 19th). Turn right at Connecticut before the intersection.

California buckeye (Aesculus californica) in bloom on 19th Street

Connecticut Street, north of 19th

12. St Teresa Church Fern-leaf Catalina ironwood (Lyonothamnus floribundus ssp. asplenifolius), Santa Cruz Island, CA native (a row of these trees on the east side of street of Connecticut, next to St Teresa). Cross Connecticut Street.

13. 394 Connecticut Camphor tree (Cinnamomum camphora), E Asia (west side of street). Cross 19th to get back on the south side, and continue east/downhill on 19th.

19th Street, Connecticut to Arkansas, south side

14. 1515 - 19th Giant yucca (Yucca elephantipes), Central America (one of the biggest in SF!)

15. 401 Arkansas Brush cherry (Syzygium australe), E Australia (tree is on 19th). At Arkansas, take a short jog to the right/north to see the next tree.

Arkansas Street, north of 19th, west side

16. 380 Arkansas Sweetshade (Hymenosporum flavum), E Australia. Backtrack to 19th and turn right/downhill

19th Street, Arkansas to Carolina, north side, below the sidewalk

16. 380 Arkansas Catalina cherry (Prunus lyonii), Catalina Island, CA (tree is on 19th). The tree is just downhill from the house - it’s one of the biggest of this species, and maybe the biggest, on SF’s streets.

17. 19th just before Wisconsin Almond (Prunus dulcis), Iran (common in the Central Valley; rare in SF)

18. 19th between Wisconsin & Carolina Shiny xylosma (Xylosma congestum), China (two trees - photo of one of the trees is below). This is an extremely rare tree in SF - a great find!)

Richard and Jason in front of a shiny xylosma (Xylosma congesta)

19. 19th at Carolina Monterey pine (Pinus radiata), Año Nuevo, Monterey, Cambria, CA native, most widely planted coniferous tree in the world (mostly for lumber). Turn left and head up Carolina, on the right (west) side.

Carolina Street, south of 19th, west side

20. 1801 - 19th European hornbeam (Carpinus betulus), Eurasia (tree is on Carolina)

21. 618 Carolina Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia

22. 664 Carolina Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia. Continue up the stairway at the end of the street.

Jack Balestreri Way (Carolina Street Steps)

23. Honey locust (Gleditsia triacanthos), E USA (east side of steps)

24. Giant sequoia (Sequoidendron giganteum), Sierra Nevada, CA native, largest tree species in the world (left/east side of steps)

[NOTE; we saw a flock of parrots in the trees adjacent to the steps, munching on plums - you can see some of the green, immature plums on the upper left of the photo.]

25. Coast redwood (Sequoia sempervirens), central and northern CA, coastal native, tallest tree species in the world (near top of the stairs; right/west side of steps)

20th Street at Carolina, north side (just to the left after you reach the top of the stairs)

26. New Zealand Christmas tree,called “pohutukawa” in Maori (Metrosideros excelsa), New Zealand. Continue uphill on Carolina on the right/west side.

Carolina Street, 20th to 21st, west side

27. 752 Carolina Water gum (Tristaniopsis laurina), E Australia

28. 800 Carolina Chitalpa (xChitalpa tashkentensis), hybrid of two native USA species

**Please cross the street carefully.** Head back downhill on Carolina on the east side of the street.

Carolina Street, 21st to 20th, east side

29. 797 Carolina Akebono flowering cherry (Prunus x yedoensis ‘Akebono’), Japan

30. 785 Carolina Pacific wax myrtle (Myrica californica), CA to British Columbia (very rare on SF streets)

31. 767 Carolina Weeping bottlebrush (Callistemon viminalis), E Australia

32. 749 Carolina Australian tea tree (Leptospermum laevigatum), SE Australia

33. 719 Carolina Lemon bottlebrush (Callistemon citrinus), E Australia. Turn right on 20th and head east.

20th Street, Carolina to Wisconsin, north side

34. west of 1819 - 20th Deodar cedar (Cedrus deodara), Himalayas

1745 - 20th Street, SE corner of Wisconsin (trees are on Wisconsin) This address has an amazing collection of mostly tropical plants. Mike Sullivan dedicated an entire page of his Trees of San Francisco book to this garden - he called it a “ten car pileup” of amazing trees and plants. Jason Dewees refers to it as a “pilgrimage site”. So take some time to appreciate what’s here!

35. Coral tree (Erythrina caffra), S Africa (at the corner of the property)

36. Nikau palm (Rhopalostylis sapida), New Zealand (this is the only palm native to New Zealnd - it is against the house as you walk uphill on Wisconsin)

37. Blackwood acacia (Acacia melanoxylon), SE Australia (large tree in sidewalk on right as you ascend Wisconsin)

38. Giant fishtail palm (Caryota obtusa), Thailand (one of the next palms you’ll see against the house - this is the one with the double pinnate fronds)

39. Coast banksia (Banksia integrifolia), E Australia (against the house further up Wisconsin)

40. Puka (Meryta sinclairii), New Zealand (smaller shrub with shiny leaves against the house)

41. Pindo palm (Butia odorata), Brazil (the last palm at this address as you ascend Wisconsin, on left). Backtrack to 20th, and head right/east.

1745 - 20th Street, SE corner of Wisconsin (trees are on 20th St)

42. Mediterranean fan palm (Chamaerops humilis), Mediterranean Basin (smaller palm at the corner)

43. Floss silk tree (Ceiba speciosa), S America (the very large tree in front of the house, planted in the sidewalk - you can’t miss this one because there are thorns on the trunk)

44. Black tree fern, mamaku (Cyathea medularis), New Zealand, Fiji, French Polynesia (large fern against the house)

45. Queen palm (Syagrus romanzoffiana), Brazil (against the house, but not the palm closest to the house - that one is a king palm (Archontophoenix cunninghamiana)

**Please cross 20th street carefully.**

20th Street, east of Wisconsin, north side

46. 1740 - 20th Shoestring acacia (Acacia stenophylla), W Australia

47. 1740 - 20th King palm (Archontophoenix cunninghamii), E Australia. Head east on 20th Street.

20th Street, Arkansas to Connecticut, north side

48. 1632 - 20th Sweetgum (Liquidambar styraciflua), E USA to Mexico & C America

50. 1616 - 20th Crape myrtle (Lagerstroemia hybrid), Asia

Connecticut Street at 20th, east side

50. 495 Connecticut Bailey’s acacia (Acacia baileyana), E Australia

20th Street, Connecticut to Missouri, south side

51. 501 Connecticut Flowering pear (Pyrus calleryana), E Asia (tree is on 20th)

52. 501 Connecticut Blue Atlas cedar (Cedrus atlantica ‘Glauca’), Morocco/Algeria (tree is on 20th)

53. 1521 - 20th Olive (Olea europaea), Mediterranean Basin. Turn left on Missouri.

Missouri Street, 20th to 19th, west side

54. 466 Missouri Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species, first discovered in San Francisco

55. 456 Missouri Avocado (Persea americana), Mexico & Central America

56. 400 Missouri Japanese maple (Acer palmatum), Japan (tree is in front of Goat Hall)

Our regular commercial: This walking tour was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; and Richard Turner, retired editor of Pacific Horticulture magazine . You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. Richard edited another great book on San Francisco trees: Elizabeth McClintock’s Trees of Golden Gate Park. If you’re a tree enthusiast, buy all three books!

Bernal Heights #covidtreetour (5-9-20)

May 04, 2020 by Michael Sullivan

This is now our fourth week of creating temporary “tree tours” in San Francisco neighborhoods by chalking tree descriptions and -> directional arrows -> on sidewalks. Word is getting out - we made the second page of the San Francisco Chronicle on Sunday when Carl Nolte wrote about our Noe Valley tour!

Yesterday (5-3-20) morning, for some reason I woke up full of energy at 6AM, and so in a burst of enthusiasm between over the next four hours, I chalked tours in the Castro (starting point = NW corner of Noe and 18th); Glen Park (start = SE corner of Chenery and Lippard) and Forest Hill (start = Forest Hill Clubhouse at 381 Magellan). If you live in those neighborhoods, please help get the word out - the chalk will fade in a week or so!

On Saturday, Richard Turner (Editor Emeritus of Pacific Horticulture), Jason Dewees (author of Designing with Palms) and I did a tour of the Bernal Heights neighborhood. Chalk fades (!) but fortunately Richard typed up detailed notes as to tree locations and direction - I’m copying Richard’s notes below:

“The tour begins with the tall eucalyptus near the corner of Eugenia Avenue and Bonview Street, just a block uphill from Cortland Avenue. Most trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers run from 1 to 37.

The walk heads west on Eugenia to Winfield, then north on Winfield to Virginia, west on Virginia to Prospect, south on Prospect to Cortland, east on Cortland to Bonview, and north on Bonview to Eugenia, the start of the tour.

Eugenia Ave, Bonview to Elsie, south side

1. 418 Eugenia Willow-leaf peppermint (Eucalyptus nicholii), SE Australia. This is the very large tree at this address. Head west (towards Elsie) from here.

2. 418 Eugenia Red ironbark (Eucalyptus sideroxylon), E & SE Australia

3. 412 Eugenia Showy honey myrtle (Melaleuca nesophila), W Australia

4. 412 Eugenia Lemonwood (Pittosporum eugenioides), New Zealand

Eugenia Ave, Elsie/Virginia to Winfield, north side

5. 332 Virginia Olive (Olea europaea), Mediterranean Basin (tree is on Eugenia)

6. 332 Virginia Bailey’s acacia (Acacia baileyana), E Australia (tree is on Eugenia)

7. 301 Eugenia Australian willow (Geijera parviflora), E & SE Australia (tree is on Winfield)

Winfield St, Eugenia to Virginia, west side

8. 266 Winfield Brazilian pepper (Schinus terebinthifolius), Brazil (tree is near top of Eugenia Steps)

9. Top of Eugenia Steps , to the right as you face the stairs Buttercup bush (Senna multiglandulosa), Mexico & S America. From the top of the stairs, turn north and head downill on Winfield.

10. 228 Winfield Himalayan white birch (Betula utilis var. jacquemontii), Himalayas

11. 229 Winfield Italian bay (Laurus nobilis), Mediterranean Basin (tree is across the street)

12. 222 Winfield Hackberry (Celtis sp.), Asia; turn left on Virginia

Virginia Ave, Winfield to Prospect, north side

13. 217 Virginia Mexican fan palm (Washingtonia robusta), Baja

Chinese elm (Ulmus parvifolia); bark closeup

14. 217 Virginia Chinese elm (Ulmus parvifolia), E Asia

15. 217 Virginia Guadalupe palm (Brahea edulis), Baja

16. 217 Virginia Southern magnolia (Magnolia grandiflora), SE USA

17. 215 Virginia Elm (Ulmus sp.), Europe

18. 201-A Virginia Brisbane box (Lophostemon confertus), E Australia (tree is on Prospect). Turn left and head south on Prospect.

Virginia Ave at Prospect, NW corner

19. 195 Virginia Pineapple guava (Acca sellowiana), Brazil (tree is on Prospect, inside fence)

Prospect Ave, Virginia to Heyman, west side

20. 120 Virginia Victorian box (Pittosporum undulatum), E Australia (tree is on Prospect)

21. 214 Prospect Little Gem magnolia (Magnolia grandiflora ‘Little Gem’), SE USA

Prospect Ave, Heyman to Eugenia, west side

22. 268 Prospect Canary Island date palm (Phoenix canariensis), Canary Islands

23. 270 Prospect Red-flowering gum (Corymbia ficifolia), SW Australia

Prospect Ave, Eugenia to Kingston, west side

24. 312 Prospect Mayten (Maytenus boaria), Chile

25. 316-A Prospect Hercules aloe (Aloe ‘Hercules’), hybrid of S African species

Queen palm (Syagrus romanzoffiana), Brazil

Prospect Ave, Kingston to Cortland, west side

26. 336 Prospect Meyer lemon (Citrus ‘Improved Meyer’) At Cortland, cross the street, turn left and head uphill on Cortland.

Cortland Ave, Prospect to Elsie, south side

27. 126 Cortland Water gum (Tristaniopsis laurina), E Australia

28. 140 Cortland Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia

29. 144 Cortland Trident maple (Acer buergerianum), E Asia

30. 146 Cortland River red gum (Eucalyptus camaldulensis), Australia (very rare - may be the only one on San Francisco’s streets)

Cortland Ave, Elsie to Bonview, south side

31. 210 Cortland Peppermint willow (Agonis flexuosa), SW Australia

***At the corner of Bonview, please cross Cortland safely; there is no stop sign or pedestrian crossing at the intersection with Bonview.*** Then head up Bonview.

Bonview St, Cortland to Eugenia, west side

32. 248 Bonview Weeping birch (Betula pendula), Europe

33. 248 Bonview Indian laurel fig (Ficus microcarpa), S Asia

34. 214 Bonview Angel’s trumpet (Brugmansia x candida ‘Double White’), Andes Mountains

Bonview St, Cortland to Eugenia, east side

35. 229 Bonview Cabbage tree (Cordyline australis ‘Atropurpureum’), New Zealand

36. 219 Bonview Mirror plant (Coprosma repens), New Zealand

37. 209 Bonview Washington thorn (Crataegus phaenopyrum) E USA (beautiful tree; one of the best of this species in San Francisco)

This walking tour of Noe Valley’s street trees was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; and Richard Turner, retired editor of Pacific Horticulture magazine . You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. One other great book on San Francisco trees, while you’re at it: Elizabeth McClintock’s Trees of Golden Gate Park, edited by Richard Turner. If you’re a tree enthusiast, buy all three books!”

Noe Valley "Social Distancing" Tree Tour (5-2-20)

April 30, 2020 by Michael Sullivan

Richard Turner (left) and Jason Dewees (right), my co-collaborators in front of two beautiful king palms

This is now my third week of creating temporary “tree tours” in San Francisco neighborhoods by chalking tree descriptions and -> directional arrows -> on sidewalks. This morning, for some reason I woke up full of energy at 6AM, and so in a burst of enthusiasm over the next four hours, I chalked tours in the Castro (starting point = NW corner of Noe and 18th); Glen Park (start = SE corner of Chenery and Lippard) and Forest Hill (start = Forest Hill Clubhouse at 381 Magellan).

Last Sunday Richard Turner (Editor Emeritus of Pacific Horticulture), Jason Dewees (author of Designing with Palms) and I did a tour around Richard’s neighborhood of Noe Valley. Richard mentioned that several of his Noe Valley neighbors were looking for a more permanent (!) record of the tour so I’m copying Richard’s notes below:

'“The tour begins with the magnificent tall eucalyptus on the east side of Noe near the top of the Duncan steps. Most trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying purple numbers run from 1 to 44. The tree walk leads north on Noe to Clipper, west to Castro, north to 25th, east to Noe, north one block on Noe to Jersey, cross the street and back south on Noe to Clipper, east to Sanchez, south to 27th, and west to Noe. Tree #44 is on 27th, just before Noe, and a block from the beginning of the tour. White arrows on the pavement provide directions whenever a turn is needed. The street numbers provided below will help when the chalk has faded. Most of the trees are planted in pockets in the sidewalk pavement; a few are planted on private property between the sidewalk and the house.

Noe Street, Duncan to 27th St, east side

1. 1413 Noe Willow-leaf peppermint (Eucalyptus nicholii), SE Australia . Head downhill (south) on Noe Street.

Noe Street, 27th St to Cesar Chavez, east side

2. 1393 Noe Olive (Olea europaea), Mediterranean Basin

3. 1393 Noe Cockspur coral tree (Erythrina crist-galli), South America

Silver mountain gum (Eucalyptus pulverulenta), E Australia

4. 1375 Noe Brazilian pepper tree (Schinus terebinthifolius), Brazil

Noe Street, Cesar Chavez to 26th St, east side

5. 1331 Noe Kwanzan flowering cherry (Prunus serrulata ‘Kwanzan’), E Asia

6. 1323 Noe Red-flowering gum (Corymbia ficifolia), SW Australia

7. (skipped)

Noe Street, 26th St to Clipper, east side

8. 1295 Noe Diamond-leaf pittosporum (Auranticarpa rhombifolia), E Australia (only one in SF)

9. 1287 Noe Victorian box (Pittosporum undulatum) E Australia

10. 1257 Noe Water gum (Tristaniopsis laurina), E Australia

Noe & Clipper streets, SE corner of James Lick Middle School

11. Italian bay tree (Laurus nobilis), Mediterranean Basin. Turn left on Clipper, head to the corner with James Lick Middle School.

Clipper Street, Noe to Castro, north side

12. Clipper & Noe Carrotwood (Cupaniopsis anacardioides), E Australia (next to the school)

13. 335 Clipper Bracelet honey myrtle (Melaleuca armillaris), SE Australia (across the street)

14. Clipper at Castro Inside the fence - the Dinosaur Garden, James Like Middle School (planted with “living fossils”; look for the dinosaur mural along the Castro wall). Of particular note:

Wollemi pine (Wollemia nobilis), E Australia (in the middle of the garden, one of the taller trees - discovered near Sydney, Australia in 1997 after thought to have been extinct for millions of years)

Dawn redwood (Metasequoia glyptostroboides), China (discovered in central China in 1944 during World War II, after thought to have been extinct for millions of years)

Castro at Clipper streets, east side, SW corner of school playfield

15. Castro at Clipper (northeast corner) Strawberry tree (Arbutus unedo) Mediterranean basin, also southwest Ireland. Cross the street at Castro and turn right (head north) on Castro

Castro Street, Clipper to 25th St, west side

16. 1518 Castro Sweet michelia (Magnolia doltsopa), Himalayas

17. 1518 Castro King palm (Archontophoenix cunninghamii), E Australia (two tall palms)

Waggie palm (Trachycarpus wagneriana), China (short palm)

18. 1514 Castro Chinese elm (Ulmus parvifolia), E Asia. Cross 25th Street and turn right on 25th.

25th Street, Castro to Noe, north side

19. 4174 25th Southern magnolia (Magnolia grandiflora), SE USA

20. 4172 25th Brazilian pepper (Schinus terebinthifolius), Brazil

21. 4144 25th New Zealand Christmas tree, pohutukawa (Metrosideros excelsa), New Zealand

22. 4136 25th Bronze loquat (Raphiolepis deflexa), E Asia

23. (skipped)

24. 4102 25th White mulberry (Morus albus), Asia (favorite food of silkworms). Turn left on Noe.

Noe Street, 25th to Jersey, west side

25. 1190 Noe London plane tree (Platanus x acerifolia), hybrid of E USA species and European species

26. 1188 Noe Trident maple (Acer buergerianum), E Asia

27. 1170 Noe Chinese hackberry (Celtis sinensis), Asia. At Jersey Street, turn right, cross the street and backtrack south on Noe on the east side of the street.

Noe Street, Jersey to 25th, east side

28. 293 Jersey Willow peppermint (Eucalyptus nicholii), SE Australia (4 trees on Noe)

29. 4098 25th Washington thorn (Crataegus phaenopyrum) E USA (3 trees on Noe)

Noe Street, 25th to Clipper, east side

30. 1213 Noe Peppermint willow (Agonis flexuosa), SW Australia

31. 1229 Noe Paul’s Scarlet hawthorn (Crataegus laevigata ‘Paul’s Scarlet’), Europe. At Clipper Street, turn left and head east on Clipper.

Clipper Street, Noe to Sanchez, north side

32. 264 Clipper Indian laurel fig (Ficus microcarpa), S Asia

33. 228 Clipper Fern-leaf Catalina ironwood (Lyanothamnus floribundus ssp. asplenifolius), CA’s Channel Islands

33. 206 Clipper Snow-in-summer tree (Melaleuca linariifolia), E Australia. At Sanchez Street, turn right and head south on Sanchez

Sanchez Street, Clipper to 26th St, west side

34. 1280 Sanchez Ginkgo (Ginkgo biloba), China

Sanchez Street, 26th St to Cesar Chavez, east side

35. 1301 Sanchez Evergreen pear (Pyrus kawakamii), Taiwan

36. 1307 Sanchez Lemon bottlebrush (Callistemon citrinus), E Australia

37. 3998 Cesar Chavez Chinese elm (Ulmus parvifolia), E Asia (3 trees on Sanchez)

Sanchez Street, Cesar Chavez to 27th St, west side

38. 1366 Sanchez Peruvian pepper tree (Schinus molle), Peru, Chile

39. 1370 Sanchez Weeping bottlebrush (Callistemon viminalis), E Australia. At 27th Street, turn right and head west on 27th.

27th Street, Sanchez to Noe, north side

40. 402 27th Jacaranda (Jacaranda mimosifolia), Brazil

41. 412 27th Water gum (Tristaniopsis laurina), E Australia

42. 446 27th Fern pine (Afrocarpus gracilior), E & S Africa

43. 476 27th Chinese pistache (Pistacia chinensis), W & C China

44. 478 27th Primrose tree (Lagunaria pattersonii), Australia & S Pacific Islands (you’re now one block from the start of the tour at 1413 Noe Street)

This walking tour of Noe Valley’s street trees was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; and Richard Turner, retired editor of Pacific Horticulture magazine and a 39-year resident of Noe Valley. You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. One other great book on San Francisco trees, while you’re at it: Elizabeth McClintock’s Trees of Golden Gate Park [NOTE from Mike Sullivan - edited by Richard Turner!]. Buy all three books!”

Presidio Social Distancing Tree Tour (4-25-20)

April 25, 2020 by Michael Sullivan

I can’t do group tree tours in the pandemic era, so recently I’ve been trying something else - grabbing a box of chalk, heading to a neighborhood and chalking a tour on the sidewalk, complete with -> arrows that lead viewers from tree to tree. Last week Jason Dewees (author of Designing with Palms, with an encyclopedic knowledge of trees) and I did a fun tour of Forest Hill (it starts at the Forest Hill Clubhouse if you’re interested). This week I heard from Blake Troxel, the Presidio’s head forester, asking if I could do a Presidio tour, so this morning (4/25/20) I headed the Presidio’s Main Post to whip up a tour there.

The Presidio has some fantastic trees - it’s one of the few places in the City where there’s room for tree roots to spread out in big lawns without concrete. And I already had a tour of the Presidio from the 2nd edition of Trees of San Francisco, so this one was easy. The tour starts at the corner of Lincoln and Funston, and heads up Funston (Officer’s row), past a gorgeous Norfolk Island pine in front of the old historic Presidio hospital. The second tree, just a bit further up Funston, is a Wollemi pine (Wollemia nobilis). i was excited to see that little tree - it’s so young that it wasn’t around when the 2nd edition of my book came out, but it’s a tree I’ve been promoting. Wollemi pine has an amazing history - it was thought to have been extinct for millions of years, and known only from fossil records, until a hiker with some plant knowledge was bushwhacking in a narrow ravine in a park 50 miles from Sydney, Australia, and found a tree he didn’t recognize. He took some cuttings back to the scientists in Sydney, who discovered it was a “living fossil” - the 100 trees in that ravine are the only ones left in the world - somehow they made it through millions of years to survive to the present day. So kudos to the Presidio for planting this one - I hope to see many more soon!

Wollemi pine (Wollemia nobilis) next to the historic hospital at the Presidio

From there, the tour heads up “officers row” on Funston past some beautiful former officer’s homes. The Presidio has planted some small Chilean wine palms (Jubaea chilensis) in the front yards of the homes - a great choice, and I can’t wait to see them grow - interspersed with Canary Island Palms (Phoenix canariensis).

The tour continues on Moraga Street, past an old Peruvian pepper tree, then a right down Graham Street, past some of the best cabbage palms (Cordyline australis) in the City. A bit further down I point out the “Centennial Tree”, a big blue gum eucalyptus (Eucalyptus globulus) that was planted on the nation’s 100th birthday on July 4, 1876.

Then right on Lincoln, past a fantastic Monterey cypress, and back to the starting point. Who knows how long the chalk will last - but if you’re reading this in April 2020, head out to the Main Post to check out the tour!

Plums are in full bloom in San Francisco!

February 16, 2020 by Michael Sullivan

Plum trees (*not* cherries - they come next month!) have been blooming all over the city this past week. Edgewood Avenue in my neighborhood of Parnassus Heights is famous for its plum trees, and some Edgewood neighbors invited the entire neighborhood this morning to an impromptu street party to celebrate the plum blossoms (the photo above is one I took today of the Edgewood plums).

The most common plum in San Francisco is the purple leaf plum (Prunus cerasifera), and of the many varieties of this species '‘Krauter Vesuvius’ is the one you see most in the City.. Back in the 1990s this was actually the most commonly planted tree in San Francisco. It's a lot less common now, but still popular, and after years of popularity, there are thousands of them around the city. The tree is gorgeous for 10 days in February, but by late June the trees start to drop their leaves, and by Labor Day they’re often leafless.

The second, and less common, type of plum is Prunus x blireana, or Blireana plum. The tree has double flowers that look a bit like carnations, with deeper pink than its more common relative, and the blooms last longer. This tree is a hybrid of Prunus cerasifera 'Atropurpurea' and a double form of Prunus mume. It was developed in France and introduced in 1906.

Winter afternoon at salesforce Park

January 04, 2020 by Michael Sullivan

Yesterday I had one of those hours that makes you just happy to be alive. I decided to do a spin around Salesforce Park at lunchtime - I hadn’t been there for a couple months, and thought it would be interesting to see the park in winter mode. As I came out of the elevator, there was an enchanting clarinet, oboe and bassoon woodwind trio, playing beautifully. After listening for a while, I started my loop. It being winter, there wasn’t much color in the park, other than a few beautiful proteas in the South African garden, but it was interesting to see the hornbeams doing their segue from green to yellow, and the California buckeyes, Chinese elms and river birches in their spare winter forms. On my way out, I passed a curious two-year-old running down the middle of the bus fountain - Inspecting the holes that had been jets of water a few seconds before. It cracked me up - she was there with her (very brave) mother, not realizing that the jets could come back at any minute. Photos and vidéos below.

Chinese elm (Chilean wine palm in the distance to the right)

This two-year-old had just seen the bus fountain in action, spurting up from below, and was checking out the holes where the jets of water had just come from.

Sadness on Mt. Sutro

November 17, 2019 by Michael Sullivan

I was walking my dog on upper Woodland Avenue today, at a spot where there is a view into the Sutro Forest. I stopped to look into the forest, and took the picture that you see here. The view is of the Woodland Creek area of Mt. Sutro, part of the “Interior Greenbelt” that is owned by the City of San Francisco. (There is a small seasonal creek in ravine here, that emerges only in wet winters.)

Mt. Sutro was once owned by Adolf Sutro, and he planted the bare (at the time) hills with various types of trees. The blue gum eucalyptus (Eucalyptus globulus, from Australia) out-competed the others, leaving a monoculture of eucalyptus in the forest. I’m actually a fan of this tree in the right place, and a vigorous forest of eucalyptus is a beautiful thing. But that’s not what you see on Mt. Sutro.

What you see in the photo is an image of a forest in sad decline. The forest floor is impenetrable ivy, which means that the forest can’t regenerate - when the eucalyptus seeds hit the ground, they disappear into the thicket of ivy, and don’t germinate. The ivy also creeps up the trunks of the trees (clearly visible in this photo), covering branches and blocking light from the trees. And the trees aren’t healthy - you can see the thinning crowns at the top of this photo.

The decline of the forest has been a slow thing, and when bad things happen slowly, we often don’t react (or even recognize them as a problem - look at climate change as an example. Fortunately, the University of California, which owns over 80% of Mt. Sutro’s acreage, is taking steps to address the forest’s decline: https://www.ucsf.edu/cgr/cgr-projects/mount-sutro-open-space-reserve-vegetation-management-plan-faq

I wish them well!

Oranges and Pomegranates on Noe?

October 13, 2019 by Michael Sullivan

On a meandering bike ride through the Mission and Castro yesterday, I discovered the 500 block of Noe, and some unusual (for San Francisco, at least) fruit-bearing trees. At 559 Noe, there’s a mature pomegranate tree (Punica granatum) in the front yard. There’s a persimmon tree and fruit-bearing avocado in the back yard, which I know thanks to the nice resident who gave me a tour, as well as a few pomegranates. And at 524-26 Noe, several orange trees (Citrus x sinensis), with the fruit still green - they will ripen in the winter. Oranges aren’t unusual in northern California, but you don’t see many in San Francisco with our cool climate. Or at least not until recently - I saw a presentation at the Urban Forestry Council recently that suggests San Francisco is headed for a Santa Barbara-like climate in 50 years.

I’ll also share a couple photos of other trees I saw along the route - a couple of swaying Mexican fan palms (Washingtonia robusta) just off of 15th Street near Guerrero, and a Norfolk Island pine (Araucaria heterophylla) with one of the most striking silhouettes that I’ve ever seen for that species (and it’s famous for its silhouettes).

And a giant yucca (Yucca gigantea), seemingly just growing out of sidewalk.

Trees I never saw growing up in Upstate New York!

Washingtonia robusta off 15th Street in the Mission — *Washingtonia robusta* off 15th Street in the Mission

Norfolk Island pine showing its symmetry

Youtube video of Salesforce Park

September 02, 2019 by Michael Sullivan

I’ve put a walking tour of the Salesforce Park up on youtube - you can find it here (or just search youtube for “Salesforce Park Walking Tour”). It’s an iPhone video - in the tour, i walk around the park’s 4 block loop, identifying trees and plants as I go. If you prefer a tour where you can see the names of the trees, you can find that one here on this website: if you’re on a desktop or laptop, just click the link above titled “Salesforce Park Walking Tour”; if you’re on a smart phone, click the navigation link at the top of your screen, and choose the link by the same name.

Amazing app to ID trees and plants

July 27, 2019 by Michael Sullivan

[NOTE: if you’re trying to find the Salesforce Park Tour, click above to navigate to “Salesforce Park Walking Tour”.]

I read an article in this month’s Bay Nature about an app that can help identify plants. I’ve tried these apps before, and always found them useless, so I was skeptical. But the article made this one sound promising, so I decided to give it a try. The app is called “Seek”, and it’s a joint project of the California Academy of Sciences and National Geographic. Here’s my report: THIS APP IS AMAZING - IT REALLY WORKS! You just give the app access to your camera, and then when you find a plant that you’re curious about, you tap the camera icon on the app and point it at the plant (hint - it’s best when you point the camera at the flowers of the plant, but I’ve seen it work from foliage and seeds also). Sometimes the app will just give you a genus, and not drill down to a specific species, but most of the time it will get you right to the species. And very helpfully, it then gives you a link to the Wikipedia page about the plant or tree.

Seek isn’t perfect, but I’d say that it works 80% of the time, which is far better than anything I’d ever seen. I’ve tried it on plants that i know, just to test it. I’ve also tried it on plants that I don’t know, gotten the results, and then looked up images on the web to confirm its accuracy. The app does make occasional mistakes, but they’re rare.

I know a fair amount about trees, but a lot less about other plants. This app is starting to change that!

The app is free - it’s called “Seek by Inaturalist” - just go to the app store on you iPhone or Android device, and download. I’ve also tried an app called “Pl@ntnet, which is also pretty good (I have actually downloaded Pl@ntnet also, as a backup to Seek, but I use Seek 90% of the time).

It’s nice to see that machine learning is finally getting to the point where these plant ID apps really work. I’m sure that they will keep getting better - something to look forward to :)

Lake Maggiore - Isola Madre

July 14, 2019 by Michael Sullivan

This small island in Lake Maggiore has been owned (together with several other nearby small islands) by the Borromeo family for 500 years. Virtually the entirety of Isola Madre is a botanical garden.

The most impressive tree on this island is a Kashmir cypress (Cupressus cashmeriana). It was planted from seed in 1862, and grew to be an immense tree-the symbol of this garden. The tree was uprooted in a tornado in 2006 (photo below of the tree below showing it lying on its side after the tornado), but the Borromeo family used extraordinary efforts to save it - a helicopter and cables to right the tree, special chemicals to limit the perspiration of water from the leaves, and constant watering for several years. The tree is still cabled, as you can see from the photo below.

The island has a beautiful palm garden with over 10 species of palm, including Chilean wine palms, Butia capitata, and others that were beyond my palm abilities :) Coming from San Francisco, where ginkgos often don’t thrive, it was nice to see that one of the biggest specimen trees on the island was a giant Ginkgo biloba.

The Kashmir cypress in 2006, after being uprooted in a tornado

lake Como - Villa Melzi

July 12, 2019 by Michael Sullivan

Today we visited Villa Melzi - a beautiful estate and garden created by Francesco Melzi d’Eril, count of Lodi and Vice president of the First Italian Republic in the time of Napoleon. He decided around 1800 to build a summer residence at Bellagio on Lake Como.

Melzi had a strong interest in botany, and European botanists at that time were very interested in “exotic“ trees, including many from North America. Europe is missing many species and genera that exist in Asia and North America (in Europe they were wiped out by the Ice Age, as their retreat trees had nowhere to retreat to the south was blocked by the Alps and the Pyrenees). So while the garden has many beautiful, huge European oaks, beech and pine species and cultivars, it also has Melzi’s “exotics” - tulip trees, Chilean wine palms, various pines from Mexico, and one of the largest deodar cedars I have ever seen (in the photo below, look for the human being in the photo to see how large it is).

The most famous trees in the garden are the London planes in a long allée on the border of the lake.

I recommend a visit for tree-lovers!

Chilean wine palms next to the Orangerie

Three tulip trees - “exotic” to an early 19th century European

Deodar cedar (for perspective, notice the humans on the right)

Pinus devoniana (native to Mexico-known as Pino blanco there)

Lake Como - Villa Carlotta

July 10, 2019 by Michael Sullivan

I’m lucky to be visiting Italy’s Lake Como for a week. Just south of the Alps, 10 miles from Switzerland open but as a semi tropical climate. One of the reasons we decided to visit was the multitude of amazing gardens in this region. Our first visit was to Villa Carlotta - a gorgeous Chilean wine palm has clearly survived many winters here. Gigantic tulip trees, European sycamores (Platanus orientalis), some pretty coral trees (Erythrina sp.) and gorgeous gardens.

Two observations from Europe so far-European lindens (Tilia x europaea) are everywhere, and in bloom now with sweet perfume. These trees are a naturally occurring cross between bigleaf (Tilia platyphyllos) and littleleaf (Tilia cordata) lindens.

And second, the European beeches are amazing here in their native region! The tree in the photo below I thought was amazing ports long, straight trunk.

Yellow New Zealand Christmas Tree in full bloom

June 23, 2019 by Michael Sullivan

I’m often asked about my favorite tree. Not the type of tree I love most, but my favorite individual tree in the entire city. This tree, at 1221 Stanyan Street in Cole Valley, is my personal number one.

For starters, the tree is one of the city’s best specimens of New Zealand Christmas tree (Metrosideros excelsa), popular for its showy red bottlebrush flowers. And, indeed, all of the many hundreds of New Zealand Christmas trees on San Francisco’s streets have red flowers, except for one—at 1221 Stanyan Street. Every June, that tree pops with spectacular yellow flowers. And it’s at its peak right now, as I write this post on June 23 (almost six months from Christmas in New Zealand).

How did this tree end up with yellow flowers? The story goes back to Victor Reiter, San Francisco’s most famous plantsman from the 1930s until his death in 1986. (See p. 73 in my Trees of San Francisco book for more on Reiter.) In 1940, there was a natural mutation of the species on tiny Motiti Island in the Bay of Plenty in New Zealand, and in the late 1950s, Reiter was one of the first Californians to obtain a cutting (for the details on exactly how that happened, see the bottom of this article). As the Reiter family lived in several homes in a three-block stretch of Stanyan Street, they planted the curiosity in front of their 1221 Stanyan address—still occupied today by a family member. And more than 70 years later, the tree is thriving. It’s a beautiful mutant with an amazing history and pedigree—and my favorite tree in San Francisco.

[The paragraphs above are mostly copied from my book, so a few years old - but here’s a June 2019 postscript: I have a cousin who lives on the west side of Stanyan Street, and her back yard fronts onto the Reiter family garden. She took me into her back porch recently, and I saw another yellow specimen, even larger than the one at 1221 Stanyan, in the garden. There are other specimens of this variety of the tree (the scientific name of the yellow-blooming variety is Metrosideros excelsa ‘Aurea’) in off-street locations - there are a couple in the San Francisco Botanical Garden, at the entrance on the left; there are a couple near the entrance to Fort Mason - they alternate with red-blooming species, which is a cool effect, and I was recently informed that there are a few in Golden Gate Park near the horse stables. It would be nice if the nursery trade had more of them!]

[From an article written by Elizabeth McClintock in the July 1968 issue of California Horticultural Journal: “ A yellow flowered form of Metrosideros excelsa has occurred in the wild of New Zealand on Motiti Island, a small island a few miles from Tauranga in the Bay of Plenty, on the northeastern coast of North Island. This form is cultivated in New Zealand (Duncan and Davies, 1965) under the name M. excelsa ‘Aurea’. It was introduced to cultivation in San Franciso by L. M. Tivol. About ten years ago a visitor to the San Francisco Business Men’s Garden Club told Mr. Tivol of seeing such a plant in the wild in New Zealand while he was on a fishing trip. Mr. Tivol expressed an interest in having the plant, and when the visitor returned to New Zealand he sent cuttings to Mr. Tivol. The cuttings were turned over to Victor Reiter who succeeded in rooting several. In 1961 Mr. Reiter exhibited a flowering specimen from his young tree at the California Horticultural Society. Mr. Reiter presented one of his trees to the Strybing Arboretum in 1964. At the present time (December 1968) this tree is about eight fee tall and in the summer of 1968 it flowered profusely.”

Street Tree SF and San Francisco tree species diversity

April 22, 2019 by Michael Sullivan

In November 2016. San Francisco passed Proposition E (now referred to as “Street Tree SF”), which moved responsibility for tree sidewalk tree maintenance from homeowners to the City of San Francisco, and created a fund of approximately $20 million per year to pay for tree maintenance. Homeowners would no longer be responsible for pruning their trees, and would no longer have liability if the trees in front of their homes trees buckled sidewalks, or toppled onto neighbors’ cars or homes.

What many people didn’t realize when Street Tree SF passed, was that under the new regime, the City would also control what gets planted on City sidewalks. In the “old days”, most San Francisco street tree plantings happened through Friends of the Urban Forest. FUF guided homeowners to good choices for trees, and the City had a (short) list of prohibited trees, but the final decision was up to the homeowner. If he or she wanted a tree that was unique or unusual, or even a tree that was terrible choice for the location, he or she got what they wanted.

Under Street Tree SF, the City (actually, the Bureau of Urban Forestry of the Department of Public Works) has the final decision as to what trees get planted. FUF is continuing to do street tree plantings, and is continuing to handle most of the street tree plantings in the City, but the final decision now belongs to the City.

I will admit that I wondered if the change from homeowner-driven decisions to City control would change the mix of trees that get planted in San Francisco. If you change from a system where individual homeowners make the decision about what to plant (based on their own sometimes quirky reasons for what to put in the ground) to a system where a city department (even if it’s well-run and well-intentioned) makes the decisions, I wondered if we would end up with a lot less diversity in the mix of species that get planted.

So – I asked Friends of the Urban Forest to share data with me. I got a copy of the tree planting data from 2015 (a conventional year prior to Street Tree SF) and 2018 (the first full year after Street Tree SF, reflecting 100% City control over tree plantings). And I pored over the results, looking for any trends that might arise from the big change in who controls what gets planted in San Francisco.

Here is what I found.

A total of 1121 trees were planted in 2015, and 1481 trees in 2018. The total number of species planted actually increased from 74 species in 2015 to 75 in 2018.

The number of unique species (trees where only one or two trees were planted in a year) went down from 29 in 2015 to 22 in 2018, but the total species number stayed the same - and there were some very interesting trees that got planted in 2018 – 7 coast banksias, 5 lilly-pilly trees, and 24 gold medallion (Cassia leptophylla) trees, for example. So overall, we’re still seeing good species diversity in what is getting planted.

And the trees that were planted the most often in 2018 were trees that generally thrive in San Francisco - the #1 most planted tree was the small leaf tristania, #2 southern magnolia, #3 primrose tree, #4 brisbane box and #5 strawberry tree (Arbutus X marina). Not surprisingly, when experts make the decisions about plantings, the most commonly planted trees are good choices for our conditions and climate. (To contrast, in 2015, the top ranked trees were #1 southern magnolia, #2 small leaf tristania ,#3 strawberry tree, #4 olive and #5 peppermint willow.)

Interestingly, two trees that used to be hugely popular in San Francisco have basically dropped off the map. In the first edition of my Trees of San Francisco book in 2003, I got FUF data on the most commonly planted trees over the two decades from 1981 to 2001 – and the #1 and #2 most popular trees for those 20 yeras were the purple leaf plum and the flowering cherry. But in 2018 only 8 cherries were planted, and zero plum trees! Each tree lover will have his or her own point of view on that, but mine is that fewer plum trees is a good thing, especially if they’re replaced with species that will thrive, look good, and absorb more carbon than a plum.