Native chamise flowering shrub turns Sonoma County chaparral hillsides a creamy white

Chamise (Adenostoma fasciculatum) is an evergreen flowering shrub in the rose family (Roseaceae) from 3 to 10 feet tall that grows from Baja California north into western Oregon and Nevada. It is commonly found in the chaparral plant community and can be so abundant in places that the dense sprays of cream-colored flowers in May and June can turn hillsides a milky color. Spent flower clusters turn rusty brown.

Thickets of chamise are called chamissal. The shrub is most often found on nutrient-poor soils in sunny, dry, rocky conditions. It tolerates serpentine soils and is often abundant there.

The shrub’s leaves are small and needle-like to resist transpiration in the harsh conditions plants grow in. Another common name for the plant is greasewood because of the resinous and flammable oils contained in the leaves. The oils serve as a deterrent to animal browsing, but also evaporate on hot afternoons, acting to cool the plant.

Low basal crowns and extensive surface roots protect against soil erosion. Chamise is adapted to fire and resprouts afterwards, but too frequent fires kill the plants.

Deer relish the new shoots after a fire and populations often then increase with young foliage as browse.

As plants age they develop an allelopathogen in the leaves that accumulates in the soil, suppressing other plant growth. The plant acts as cover for birds and other wildlife that frequent the chaparral. The flowers are attractive to a variety of bees and butterflies, and goldfinches eat the seeds.

Kate Frey can be reached at katebfrey@gmail.com.Website: freygardens.com. On Twitter @katebfrey