California buckeye
By Jutta Thoerner UCCE Master Gardener
Aesculus californica
Tree size: up to 30 feet tall
Bloom description and season: spring flowers are white to pale pink, 6-8 inches long and 2-3 inches wide
Pruning needs: prune during dormant season
Exposure: sun to partial shade
Water needs: regular watering during the first growing season.
The buckeye tree is a fascinating specimen. It can grow in a wide range of conditions from moist, partially shaded canyons to dry south facing slopes or hilltops. It can be found as a single tree in dry grasslands or mixed with evergreens or oaks in forest environments. Seeds can be planted at a depth of twice its diameter in well-worked, loosened soil. In 2- 3 years the plants will produce their first bloom.
For home gardeners, it is planted as an ornamental tree because of the beautiful lime colored foliage, unusual leaf buds, and fantastic white and very fragrant spring flowers. The leaves turn red-brown foliage in late summer, often completely defoliating in summer leaving large pear-shaped fruits hanging on bare branches. This tree changes its look again when showing off graceful silver branches through the winter.
The buckeye tree, with all its beauty and stately presence, comes with a long list of cautions. Its bark, leaves and fruit contain the neurotoxic glycoside aesculin, which causes hemolysis of red blood cells. The nectar and pollen of the flowers is toxic to honeybees. However, the flowers produce ample nectar and many species of butterflies consume the nectar without problems.
The buckeye fruit gives rise to seeds that are smooth, mahogany brown with a large gray spot which resembles the eye of a deer. These are a favorite snack of chipmunks and squirrels but should not be eaten by livestock. Many Native American tribes made use of the seeds by going through a complex soaking and leaching process to remove the toxins and tannins making the nut safe to eat.
If you want a tree in your landscape that will be around for up to 300 years, the California buckeye will be up for the job.