Lotus scoparius, also known as Deerweed or California Broom, is a short-lived perennial member of the legume family (Fabaceae), and native to much of California.
Growing at elevations below 5000 feet this wild-looking sub-shrub has an open, and airy informal habit.
Deerweed is frequently found in coastal sage and interior sage scrub, and common in recently disturbed soils. It is one of the first, and most prominent, native California plant species to re-emerge after wildland fires, where it serves to enrich post-fire nutrient devoid soils with nitrogen.
Before living here, we likely wouldn’t have given this plant a second look. However, there are at least a dozen large specimens of Lotus scoparius that have volunteered on the farm in the last couple of years, since we cleared the diseased and invasive plants, growing on the south slope by the orchard and gardens.
Deerweed blooms in the early summer in our area along the coast, and is a welcome sight as many of our early spring wildflowers fade. The tiny flowers emerge a vivid shade of yellow, opening from the base of the stem toward the tip.
Once successfully pollinated the flowers turn an orange-red, which is less attractive to bee pollinators (bees see red as black), encouraging them to target the blooms that have not yet been visited.
As we’ve allowed these plants to establish themselves around the edges of the garden, we now have a few large groupings of Deerweed spilling down the bank near the bee hives.
Here they keep company with native sticky monkeyflower, hedge nettle, and cudweed.
This morning this bank was a-buzz with both native and honey bees busily working blooms.
In previous years we’ve appreciated seeing the flowers, but now that we have hives of honey bees on the farm, we’ve discovered that honey bees favor Lotus scoparius blossoms for their nectar over most other plants currently in bloom here.
Everywhere you look, there are bees!
Last year we primarily noted bumble bees frequenting the flowers, especially the Yellow-faced Bumblebees (Bombus vosnesenskii). This morning though, the honey bees were easily outnumbering the bumble bees by at least 20:1!
Sadly, one rather less active Carpenter Bee (Xylocopa spp.) seems to have chosen the flowers of L. scoparius as its final resting place.
Lotus scoparius is popular with other pollinators as well, especially butterflies. It serves as an important larval food resource for numerous species, including the Acmon Blue (Plebejus acmon), Bramble Hairstreak (Callophrys dumentorum), and our locally common Gray Hairstreak (Strymon melinus), and Variable Checkerspot (Euphydryas chalcedona) butterflies that are frequently sighted on the farm.
The leaves, consisting of 3-6 leaflets are pinnate, and sparsely spaced along the length of the stem.
The roots of Lotus scoparius have been used by native Californians to make soap, and the stems often used by the Costanoans as building material, and a decoction of leaves as a remedy for coughs.
Plants grow in full sun, to partial shade, and once established require zero supplemental irrigation. None of the plants here are irrigated. Each plant grows up to 3 feet tall and equally as wide, but hold much more presence in the garden if they’re planted, or allowed to self sow, in large drifts.
As with many of our native blooming plants, Lotus scoparius goes dormant in the summer months, shedding its leaves by mid-late summer, but re-emerging with the spring rains.
Unfortunately, Lotus scoparius does not transplant well, and as such it is not a plant you’re likely to find in your local nursery. Deerweed is best direct sown from seed in the fall, or allowed to self sow from established plantings. Deerweed is easily outcompeted by dense brush, and in the wild it often disappears as other understory plants fill in, so to preserve plantings in a garden setting it’s essential to keep the area free of dense stands of grasses, and weedy vegetation.
Like many California native plants, the seeds of L. scoparius have a thick seed-coat, and when buried in soils the seeds can remain dormant for long periods of time, until they are abraded, or stimulated to germinate as a result of weathering or fire.
After spending countless hours diligently removing the invasive French Broom on the property, we welcome the sight of this native California Broom species, and hope to encourage more of it to grow along some of our steep sandy slopes. Although more diminutive in stature, Lotus scoparius has a very similar appearance, both in leaf shape, and flower shape, to the more aggressive non-native broom species. This species however, as a host plant, and food resource for so many native (and non-native) pollinators, is much more welcome to grow here.
 Daniel E. Moerman’s Native American Ethnobotanical Database
 Barbour, M., Keeler-Wolf, T., and Schoenherr, A. 2007. in Sage Scrub: Terrestrial Vegetation of California. University of California Press.