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.

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.

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!