California Buckeye: Survivalist Beauty, but Foreign Appetites Beware

A ridge-top California buckeye. Photo: US Forest Service

The flower, which is typically 6–8 inches long and 5–8 inches broad. Photo: Tim Berger

The green leaves. Photo: Cliff Hutson

The large seed and leathery pod. Photo: Martin Jambon

A germinating seed. Photo: Martin Jambon

A flowering California buckeye. Photo: Mark Miner

The majestic seeds hang on the leafless tree. Photo: Martin Jambon

A dormant California buckeye. Photo: David Prasad

California buckeye nestled among the oaks. Photo: Jitze Couperus

The California buckeye (Aesculus californica) is the smart spring bride of the dry canyons of the central coast ranges and Sierra Nevada mountains to about 4,000 feet. She throws a showy party but knows dry times are coming, ends it early, and is picky about whom she serves.

The entire life strategy of the California buckeye optimizes for economical water use. It is the first shrub (small tree) to leaf out every year and grows rapidly in the wet winter and spring months when its neighbors are still dormant. It finishes its creamy, fragrant floral show by the end of June, loses all its leaves, and then enters dormancy by mid- to late summer, although in cooler coastal climates the leaves might hang on until fall. The bark, leaves, and large eye-catching seeds are toxic to most animals. The pollen and nectar, although safe to many butterflies, hummingbirds, and native honeybees, make non-native bees sick, so that it’s a common problem for beekeepers. A “buckeyed-bee” hatches with deformed legs, body, and crippled wings.

Late May into early June is a great time to spot the California buckeye when it’s in its full flowering glory.