American birdsfoot trefoil
Acmispon americanus
Care
full sun, part shade
low
Fast, Medium, Slow; Adaptable.
1–1ft tall , 1–1ft wide
Mar-Aug
Friendly
Coastal bluffs and grasslands from Mendocino County to Monterey County, below 1000 ft elevation in sandy or gravelly soils.
Care Guide
Planting
Plant American birdsfoot trefoil in full sun in a spot with fast to slow draining soil - it's highly adaptable and will tolerate whatever you have. This native annual thrives in spring, so plant in early spring for the best results. Space plants about a foot apart since they grow to about 1 foot tall.
After Planting
Water moderately through the first growing season to help establishment, then cut back to low water once established - you'll only need to irrigate about once a month in summer, if at all. As an annual, expect it to bloom from March through August before naturally declining. The biggest mistake is overwatering; this tough native plant actually prefers drier conditions once it's settled in, so err on the side of neglect rather than generosity.
Visit Calscape for more information about American birdsfoot trefoil
Endangered & Threatened Species Supported
California state threatened species (nominate subspecies)
Wildlife Supported
Insects
Host plant for larval development; critical for population maintenance in California
Host plant for larval development; multiple broods during growing season
Uses legumes including trefoil for larval development
Uses trefoil as host plant for larval development in California grasslands
Legume specialist; multiple generations on host plants
Native bee specialist; forages available flowers for pollen collection
Host plant for larvae; multiple generations in California
Polyphagous species; uses trefoil as supplemental host plant; multiple generations
+4 more species
Birds
Primary seed consumer; important food source especially in fall and winter when other resources limited