Tree of the Week: Ohio buckeyes? This one’s a native of California

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California buckeye -- Aesculus californica

The California buckeye is the wild and graceful relative of the stately horse chestnut tree with the magnificent red or white upright flower spikes and the big hand-shaped leaves. This California native, whose seeds resemble the big brown eyes of bucks (male deer), grows at lower elevations throughout our coastal ranges and the Sierra Nevada.

All parts of the plant are more or less poisonous. Local Pomo, Yana and Luiseno Indians used ground seeds to stun and catch fish. However, after roasting, grinding and leaching, the seeds are edible. Flower nectar may be toxic to honeybees, but attracts hummingbirds and butterflies. Carl Linnaeus, the Swedish botanist, named the genus after the Latin name for an oak tree bearing edible acorns.

The deciduous California buckeye grows at a slow to moderate pace to a long-lived, often multi-trunked, open, 15-to-25-foot round-head, vase or umbrella shape. The bark is thin and gray and becomes mottled whitish on older trees. Twigs are smooth and reddish brown when young. Opposite leaves are palmately compound, consisting of five to seven 4-to-6-inch-long, 1 1/2-to-2-inch-wide leaflets joined on a central stalk. Small, sweetly fragrant, white or pink flowers are borne on 4-to-8-inch-long upright plumes that grab attention. Pear-shaped, leathery capsule-like fruits contain one, sometimes two, 1-to-2-inch-long shiny, orange-brown seeds.

The tree is drought-resistant once established, but in the garden looks better with some summer water. Without extra water it starts dropping its leaves in midsummer and may stand bare for two seasons. A low-maintenance tree that seldom needs pruning, it likes partial shade to full sun and is not fussy about soil. It makes interesting bonsai material.

Forty years ago the California buckeye tree pictured above, located near Strawberry Creek at the UC Berkeley campus, seemed close to death. It was hollow, ghostlike and literally a shell of its former huge self. On a recent visit to the campus I wanted to see if any trace of the tree remained. Not only was it still there, but it was actually in much better shape, no doubt thanks to some special care and attention. Even with a hollow trunk full of holes, it had grown new branches and a healthy central core, while fruit hung from its branches.

-- Pieter Severynen

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