The rooftop park on the Salesforce Transit Center is a spectacular amenity – a 5.4 acre botanical garden and arboretum that was dropped into the city’s financial district when it opened in August 2018 (and then promptly closed a month later after an embarrassing structural problem was discovered). Ten months later, we finally know that the park is reopening on July 1 - and no doubt the pent-up demand will trigger throngs of visitors.

As wonderful as the park is, I’ve heard from many visitors that they wish the trees and plants in the garden were identified or labeled.  I know a thing or two about San Francisco’s trees, and decided that I could do something to help.  So until the park gets around to identifying its amazing flora, this walking tour is my contribution to those who love the park, but wish they knew more about what they were seeing. 

Much of what I am sharing below I know because Adam Greenspan, the landscape architect at PWP Landscape Architecture who led the design of the park, was kind enough to give me a personal tour of the park just before it opened.  Greenspan did an amazing job curating hundreds of trees and thousands of plants from around the world, and grouping them in themed gardens (a Chilean garden, a South African garden, and so on), leaning heavily on plants from Mediterranean regions around the world that will thrive in our northern California climate.  His deep plant knowledge and interest shines everywhere in the park. 

From the ground floor of the transit center, ascend the escalator until you reach the top level.  Turn right, and continue until you reach the path that circles the park.  On your right will be a grove of Brisbane box trees from Australia (or Lophostemon confertus if you’re a botanist), one of San Francisco’s most common street trees.  Interspersed among the trees are small cycads, also native to Australia (they look like very short, small palms – the scientific name is Macrozamia communis).  Turn left at the pathway to begin a tour of the park’s palm garden.  On your immediate left are a grove of kentia palms (Howea forsteriana) from Lord Howe Island, east of Australia – they’re the palms with the striped trunks.  Just past these palms is a grouping of six Nikau palms (Rhopalostylis sapida), New Zealand’s only native palm – you’ll see them just before you reach the exit sign leading to stairs on your left.  

Chilean wine palm ( Jubaea chilensis )

Chilean wine palm (Jubaea chilensis)

As you continue, on your left you’ll pass a number of palm trees of different species, but behind them you’ll see a large palm in the lawn with very large trunk.  It’s one of the most spectacular trees in the park - a Chilean wine palm (Jubaea chilensis), native (of course) to Chile. This species is the second most massive type of palm in the world, but it’s very slow growing, so it’s impressive to have such a large one here in the park.  

This palm garden is a ten-car pileup of different species - it’s too hard in this tour to identify them, but among the trees you’ll see are sentry palm (Howea belmoreana) from Lord Howe Island, ribbon fan palm (Livistona decora) from Australia, Guadalupe palm (Brahea edulis) from Guadalupe island, Mexican blue palm (Brahea armata ‘clara’) from Baja California, Quito palm (Parajubaea cocoiodes) from Ecuador and Columbia, kumaon palm (Trachycarpus takil) from northern India and Nepal, and miniature chusan palm (Trachycarpus wagnerianus) from the foothills of the Himalayas.

One species that’s easy to ID are the smaller, multi-trunked palms in the garden - these are Mediterranean fan palms (Chamaerops humilis) from North Africa and southern Europe - the northernmost palm species in the world. 

The last palm tree on your left in the palm garden – rather large, with graceful curved fronds, is a pindo palm (Butia capitata) from Brazil. Continuing on the path, on your left you’ll see a glass dome ringed by tall palm trees – these are Mexican fan palms (Washingtonia robusta) – the same tree that lines Mission Street in the Mission District. 

California buckeye in foreground; Monterey cypress trees upper left

California buckeye in foreground; Monterey cypress trees upper left

Soon you will then cross two white stripes on the path – marking a seismic stability feature.  The Salesforce Terminal is actually three buildings, and the white stripes mark the gaps between the buildings – in an earthquake the gap is intended to break the wave energy of the earthquake.  Just past the stripes, on your left are several gnarled African sumacs (Rhus lancea) from South Africa, followed by a Monterey cypress (Hesperocyparis macrocarpa), native to California’s central coast (and very common in San Francisco’s parks), and then a small California buckeye (Aesculus californica), which is a Bay Area native.  Across the path, on the other side of the glass wall are five Catalina ironwoods (Lyonothamnus floribundus), native to the Channel Islands of Southern California. 

Continue past the exit sign. On your right on either side of the glass wall are strawberry trees (Arbutus X Marina).  This tree is a natural hybrid of two Arbutus species - the hybrid was first discovered in the 1915 Pan Pacific International Exposition in Golden Gate Park (which got the trees from the closing sale of a nursery in San Francisco’s Marina district – hence the name).  It was later introduced to the nursery trade, and is now one of the most commonly planted street trees in San Francisco.   Continue past some Japanese maples (Acer japonica) on your left. The two pine trees on your right are torrey pines (Pinus torreyana), native to Southern California, followed by two more Monterey cypress trees. 

dragon tree ( Dracaena draco )

dragon tree (Dracaena draco)

Continuing on the path you’ll see the first of a large number of narrow, vertical European hornbeam trees (Carpinus betulus'Fastigiata') which line the lawn. Continue until you reach the desert garden at the western end of the park – filled with cacti and other succulents. The “stars” of this garden are the dragon trees (Dracaena draco), native to the Canary Islands and Madeira - there are three of them in this garden.

The path now turns left as you head south, until you reach the second desert garden on your right. This garden is full of aloes, as the signage explains. The large tree-like aloes are coast aloes (Aloe thraskii) from South Africa.  

The path now turns again to head east, where you’ll reach the park’s “fog garden”, full of plants that have evolved to use fog to survive.  The first tree here is a pink melaleuca (Melaleuca nesophylla) from western Australia – a shrublike tree with pink flowers if in bloom. 

monkey puzzle trees ( Araucaria araucana )

monkey puzzle trees (Araucaria araucana)

Now on your left you will see three mayten trees (Maytenus boariafrom Chile in the lawn (these trees have a drooping habit that reminds many of weeping willows), and then another mayten to the right of the path.  You are now in the park’s Chilean garden – on your right you’ll see three striking monkey puzzle trees (Araucaria araucana) on your right.  You can’t miss them – they are the trees with the spare, symmetrical shape and sharp, scaly leaves.  These trees are native to Chile and western Argentina.  If you look to the left of the path, you’ll see some close botanical relatives of the monkey puzzles – three Norfolk Island pine/cook pine hybrids in the lawn.  Both the Norfolk Island pine (Araucaria heterophylla) from Norfolk Island and cook pine (Araucaria columnaris) from New Caledonia are in the same Araucaria genus as the monkey puzzles – think of them as siblings in the plant world. 

As you continue, the large tree with the round crown in the lawn on your left is a Chinese elm (Ulmus parvifolia), native to eastern Asia, and San Francisco’s most commonly planted elm. There are two others nearby in the lawn.  You will next enter the South African garden on your right.  The first trees in this garden are three silver trees (Leucadendron argenteum), with distinctive silvery green leaves. This species (called silwerboom in Afrikaans) is endangered in the wild; it’s native to a very small area near Capetown.  

Queensland bottle trees ( Brachychiton rupestris )

Queensland bottle trees (Brachychiton rupestris)

Continue to the children’s play structure.  On on your right as you pass the climbing gym are three African fern pines (Afrocarpus gracilior), native to Kenya, Tanzania, and Uganda. Further along on the right are two very large Queensland bottle trees (Brachychiton rupestris), the trees with the swollen trunk at the base (the swollen trunks are an adaptation to dry climates - they allow the tree to store water during rainy periods, which can be drawn upon during drought periods). Further along, you’ll see two trees with maple leaf-shaped leaves – these are also in the Brachychiton genus; the common name is flame tree (Brachychiton asplenifolius).   This tree gets its common name from the bright red bell-shaped flowers that often cover the entire tree when it is leafless. 

champak trees ( Magnolia champaca )

champak trees (Magnolia champaca)

Continue to the plaza, with tables and chairs on your left. The trees in the plaza are California sycamores (Platanus racemosa ‘Roberts’), a native California tree, common in riparian valleys in the from the Bay Area south to Baja California.  It is “undeservedly rare” on San Francisco streets – I’m hoping that this prominent placement of the tree will inspire more of them citywide. As you continue, to the right of the path are three champak trees (Magnolia champaca), native to the Indian subcontinent and southeast Asia.  Another common name is “joy perfume tree” – the white flowers of the tree are very fragrant.  As you continue east, you will pass an olive tree (Olea europaea) on your right, followed by another strawberry tree. 

As you continue on your right you will see a sign for “Mediterranean gardens of the world”. The palms near the sign are Mediterranean fan palms (the same species that we saw in the palm garden earlier). The next trees on the right, with the grey furrowed bark, are cork oaks (Quercus suber), native to Portugal, Spain and other spots in the western Mediterranean – the bark of this tree is the source of the cork used in wine bottles.  On your left you’ll see a solitary cork oak, followed by a grove of California natives as you look into the lawn - a mix of California buckeyes and a couple of coast live oaks (Quercus agrifolia), the tree with the smooth grey bark.  

 Continue until you see the entrance to a building on your left (the building is 181 Fremont – which holds Instagram’s headquarters on its lower floors, including this one).  To the left of the path just before you reach the building entrance is a Persian ironwood (Parrotia persica), native to Iran and Azerbaijan - it’s the tree with the vertical cracks in its trunk.  

Further down the path you’ll enter the prehistoric garden, one of my favorites in the park. Most of the trees and plants here date back millions of years, to the time when dinosaurs roamed the earth.  The first tree on the right is a ginkgo (Gingko biloba), followed by two joy perfume trees, followed by another ginkgo. Then you’ll reach a spectacular giant cycad – I’m not sure of the species, but it’s one of the most impressive plants in the park.  Next is a Queensland kauri tree (Agathis robusta), native to northern Australia and New Guinea, followed by two more monkey puzzles trees.  

Wollemi pine ( Wollemi nobilis )

Wollemi pine (Wollemi nobilis)

The next tree in the prehistoric garden is my favorite in the entire park. It doesn’t jump out at you – it’s the evergreen tree that is perhaps seven feet tall, four feet wide, with graceful pinnate leaves.  I love it for its recent history:  scientists knew this tree from fossil records, but it was assumed to have been extinct for millions of years.  Until … September 10, 1994, when David Noble, an Australian park ranger with some botanical knowledge, bushwacking in a remote canyon in Wollemi National Park near Sydney, discovered a grove of trees he didn’t recognize.   He brought some specimens back to Australian scientists, who identified it as the same tree they knew from fossils.  (Imagine finding a few Stegosaurus hanging out in a remote Pacific island - for botanists, it’s like that.) Fewer than 100 specimens survive in the wild (the location of the grove is undisclosed, to protect the trees).  Scientists named the tree Wollemi nobilis to honor Noble. The common name is Wollemi pine, although the tree is not a true pine – it’s actually in the Araucaria family, more closely related to monkey puzzles and Norfolk Island pine trees.     

As you turn the corner and head left (north), you will see three river birches (Betula nigra), native to the eastern United States, in a circular planting in the corner of the park. The low lying plants with gigantic leaves in this garden are Gunnera manicata, known as giant rhubarb, or - my favorite common name in the park - dinosaur food (it’s an ancient plant).  As you reach the northern end of the path, you’ll see three more river birches on your right. The irises in this garden are from the Neomarica genus; the common name is “walking iris” – the flowers of this plant are followed by plantlets that grow in weight until they hit the ground, allowing the plantlet to root (or walk) away from its parent.   

Turn the corner and head west back to your starting point.  On your right will be a deodar cedar (Cedrus deodara) from the western Himalayas, followed by an incense cedar (Calocedrus decurrens) from California and Oregon, and then a torrey pine (these three species are repeated in the garden on the right for a while).  

The large tree opposite the beginning of the bus fountain is a southern live oak (Quercus virginiana), native to the American southeast. 

As you continue on your right, you will see another deodar cedar, followed by seven coast redwoods (Sequoia sempervirens), the tallest tree in the world, and the redwood native to Muir Woods and coastal northern California.   There are several coast redwoods on your left as well.

You will now approach the entrance to the Salesfore Tower on your right (only Salesforce employees are allowed to use this entrance).  The unusual vertical looking trees on either side of the entrance to the tower are actually giant sequoias – the gigantic trees from the Sierra Mountains.   Here, the landscape designer chose a variety that has a vertical, fastigiate shape (Sequoiadendron gigantea ‘Pendula’).  Just past the giant sequoias, you have Brisbane boxes on either side of you – the trees that we saw at the beginning of the tour.   Continue until you return to your starting point where you can turn left and take the escalator back to the street. 


Small advertisement:  if you enjoyed this tour, my book, Trees of San Francisco, has 12 more tours of interesting San Francisco neighborhoods, taking you past landmark trees (and some quirky only-in-San Francisco non-tree stuff that I’ve discovered).   There are tours of the Mission, Potrero Hill, Pacific Heights, the Castro, Noe Valley, the Presidio, Cole Valley, Forest Hill, the Financial District, Parnassus Heights , the Golden Gate Park panhandle, and Upper Market’s staircase streets – a dozen tours in all.   And descriptions of 70 trees that you’re likely to find on San Francisco streets.   Available on Amazon, or even better at your neighborhood bookstore!

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