Self-Guided Tree Walk: Old Palo Alto

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The Old Palo Alto Tree Walk begins at Gamble Garden Center, 1431 Waverley Street, Churchill Avenue parking entrance.

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1. Coulter Pine (Pinus coulteri)

444 Churchill Avenue, pine on the right

Unusual for this area, this pine with 8–12" needles crowded at the ends of thick twigs is native to central and Southern California between 3,000' and 6,000' in elevation. Native Americans once gathered and ate the large seeds. The shorter-needled pine to its left is a Monterey Pine (Pinus radiata).

2. Coast Live Oak (Quercus agrifolia)

474 Churchill Avenue, large street tree on Cowper Street near the corner

Native mainly to California's coastal ranges, Coast Live Oak is frequently associated with California Bay Laurel, Madrone, Toyon, and other native oaks. It grows best in well-drained soil. The acorns that drop in the fall can produce young oaks very readily. Native oaks do not tolerate summer water and should not be planted in lawn areas.

3. Snakebark Maple (Acer capillipes)

475 Coleridge Avenue, 3 young street trees on Cowper Street

Green and silver striped bark is the unusual feature of this attractive maple tree. One of these three trees is probably a different cultivar from the other two as its leaf shapes and fall color patterns are different. Snakebark Maples are known for growing well in shady locations.

4. London Plane Tree (Platanus x acerifolia)

508 Coleridge Avenue, 5 street trees on Cowper Street

This fast-growing tree is used extensively as a street tree in Palo Alto due to its deep roots and tolerance of the urban environment. Notice the beautiful bark and large arching canopy and the tree roots' struggle to remain contained in the narrow planting strip.

5a. Canary Island Pine (Pinus canariensis)

1631 Cowper Street, left front corner

This pine tree native to the Mediterranean is an excellent replacement for Monterey Pines and other conifers subject to borers. It tolerates a dry summer and is relatively pest free.

5b. Arbutus Marina (Arbutus 'Marina')

1631 Cowper Street, between the front door and the driveway

Related to, but more adaptable than, the native Madrone (Arbutus menziesii), this Arbutus tolerates typical gardening conditions and regular watering as long as the soil is well-drained. Take a good look at the beautiful bark and, if it is spring or fall, the colorful fruit. The largest known specimen was planted in a San Francisco garden in 1942 and has reached a height and spread of 40'.

6. Bradford Pear (Pyrus calleryana 'Bradford')

468 Lowell Avenue, 2 street trees

A white-flowering ornamental pear, it grows to about 40' and has beautiful spring bloom and late fall color in December. The 'Bradford' cultivar has very poor structure and if not pruned extensively, trees can literally fall apart. 'Aristocrat' and 'New Bradford' are good replacements.

7. Coast Redwood (Sequoia sempervirens)

1709 Waverley Street, tall tree right of the driveway on Lowell Avenue

When you plant this tree, remember it is one of the tallest tree species in the world. Count on branch spread at the base (tip to tip) of 14–30' wide. Centuries-old natives surpass 350' high, but 70–90' can be expected in 25 years. In its native coastal ranges of California and Oregon, the Coast Redwood collects fog with its needles, which drips down and provides moisture all year long. This thirsty tree requires ample regular water and will not tolerate drought.

8. English Walnut (Juglans regia)

1727 Waverley Street, 2 street trees

The English Walnut provides walnuts to eat and wood for furniture. It is one of the last trees to leaf out in the spring. By June, green-husked walnuts start to form. In the fall when they are ripe, you can remove the husk to find the familiar walnut.

9. Paul's Scarlet Hawthorn (Crataegus laevigata 'Paul's Scarlet')

350 Tennyson Avenue, 2 street trees on either side of the front walk

This small tree is native to the English midland forests. This cultivar, 'Paul's Scarlet', has been produced since 1858 and has become a favorite for parks and gardens. It produces rosy-pink flowers in the spring and red berries that persist into the fall.

10. Incense Cedar (Calocedrus decurrens)

327 Tennyson Avenue, next to the sidewalk in the right front corner

Common in the Yosemite Valley floor, this native evergreen conifer is sometimes confused with the Coast Redwood because of its reddish brown bark. Initially slow growing, when established it can grow 2' per year and will reach 75–90'.

11. Giant Sequoia (Sequoiadendron giganteum)

310 Tennyson Avenue, 3 trees in a cluster in the left side of the front yard

It looks like an incense cedar, but is closely related to the Coast Redwood. This is the largest tree and actually the largest living organism in the world; at higher altitudes massive trunks can reach a diameter of 30'. It is native to the western slopes of the Sierra Nevada.

12. Copper Beech (Fagus sylvatica 'Atropunicea')

299Tennyson Avenue, on Bryant Street on the right property (fence) line

The Latin (and scientific) name for the beech genus Fagus comes from a Greek word for eating. The oil-rich, peanut-sized nuts found inside the woody prickled fruit case have been favored as a treat since the Stone Age.

13. Mayten Tree (Maytenus boaria)

1750 Bryant Street, small tree right of the front door

This native of Chile has narrow 1–2" long light to medium green leaves that are held perpendicular to the twigs. Its beautiful weeping form is similar to the Weeping Willow (Salix babylonica). Water deeply to reduce the likelihood of surface roots. This species is a poor performer in this area.

14. Western Catalpa (Catalpa speciosa)

290 Lowell Avenue, 6 street trees on Bryant Street

The leaves are large, bold, and heart-shaped. In late spring, large clusters of trumpet-shaped flowers appear. The flowers, white with yellow markings and lavender spots, are followed by long, bean-shaped seed capsules that stay on the tree for a long time.

15. Western Red Bud (Cercis occidentalis)

300 Lowell Avenue, 2 trees right of the driveway

This deciduous California native with almost-round leaves grows in the foothills below the 4,000' level. As a shrub or small tree it reaches 10–18' high and wide. In spring it has a stunning three-week display of magenta flowers.

16. Colorado Blue Spruce (Picea pungens)

340 Lowell Avenue, just inside the driveway gate on the left

This American favorite is native to the Rocky Mountains at altitudes up to 10,000'. It is often found as a solitary tree on dry slopes or next to dry creek beds. Notice that the cones hang from the branches, unlike the Deodar Cedar, which has cones on the tops of the branches. In gardens it reaches 30–60' and 25–35' wide.

17. California Black Oak (Quercus kelloggii)

353 Lowell Avenue, street tree left of the driveway

Native to the hills of California and Oregon at elevations of about 2,000' to 3,500', this deciduous oak has handsome foliage that emerges soft pink, matures to glossy dark green and turns yellow and orange in the fall. Its acorns are 1½" long with the cup covering half the acorn. They mature in the fall of their second year.

18. Shumard Oak (Quercus shumardii)

1651 Waverley Street, 3 street trees

Native to the southeastern U.S. and commonly used as a street tree there, this deciduous oak likes moist soil. It has large 1" acorns with a shallow cup. Some specimens have good fall color. Shumard Oaks belong to the red oak group along with Red Oaks and Pin Oaks.

19. Black Locust (Robinia pseudoacacia)

375 Coleridge Avenue, street tree on Waverley Street near the corner

Because emigrants brought seeds with them from the eastern U.S., Black Locust is now common everywhere in the West. Older specimens, such as this one, have deeply furrowed bark and are often hollow. It is a deciduous tree with oval leaflets arranged opposite each other, and the smaller woody branches typically have thorns. In the spring, many clusters of white flowers appear. Structural problems make it a poor choice in Palo Alto; elsewhere in California its invasiveness is a problem.

20. Zumi Calocarpa Crabapple (Malus x zumi 'Calocarpa')

1550 Waverley Street, 2 street trees and 2 front yard trees

A small deciduous tree suited for many locations in the urban landscape. Most mature at 15–25'. Crabapples come in weeping and upright forms with flowers ranging from white to rosy pink and small fruits that may or may not appear. The trunk often has an interesting form. 'Robinson' is a tough drought-tolerant selection, and 'Echtemeyer' is a small graceful weeper.

21a. Crape Myrtle (Lagerstroemia indica)

1530 Waverley Street, 2 street trees on either side of the front walk

These deciduous trees have small leaves opposite each other on branches. In addition to their stunning bark and bright late summer flowers, Crape Myrtles provide beautiful fall color. To guarantee a tree resistant to powdery mildew choose one of the "Native American Tribe" cultivars. Good for small gardens and drought-tolerant.

21b. Flowering Dogwood (Cornus florida 'Cherokee Daybreak')

1530 Waverley Street, 2 street trees and a tree at the right front corner of the house

A U.S. native, this small deciduous tree is suitable for smaller gardens. Its 2–4" oval leaves turn bright red in fall, and it produces showy white bracts in springtime. Provide good drainage and regular water. Plant as an understory tree in partial shade, as leaf scorch can occur during the summer months when plants are located in a full sun exposure.

22. Coast Live Oak (Quercus agrifolia)

410 Churchill Avenue, street tree at the corner of Waverley Street

This is an example of a tree fighting to survive in an unhealthy environment. Notice how the root crown is impacted by the sidewalk and asphalt. The soil compaction creates anaerobic (without air) conditions in the soil, which is favorable to root rot organisms. Not feasible here, the removal of some paving would improve this tree's environment.

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Trees protected by the City of Palo Alto tree ordinance

A permit is needed to remove or prune these trees.

Check the City of Palo Alto Tree Regulations.

Trees with low watering needs

These trees are best adapted to our climate and water availability.

Thirsty trees

These trees require frequent summer irrigation and will suffer from the drought cycle in our area.

Do not plant unless you are aware of a water source such as high water table or creek proximity.

Trees not recommended for planting

These trees are either invasive, do not perform well or create infrastructure or other problems.