Coyote Brush

Appearance

The "Baccharis pilularis" shrub is generally smaller than 3 metres in height. Erect plants are generally mixed with prostrate plants. It is glabrous and generally sticky.

The stems are prostrate to erect which branches spreading or ascending. The leaves are 8–55 millimetres long and are entire to toothed and oblanceolate to obovate, with three principal veins.

The flower heads are in a leafy panicle. The involucres are hemispheric to bell shaped. This species is dioecious. Both staminate and pistillate heads are 3.5–5 millimetres long. Phyllaries are in 4–6 series, ovate, and glabrous. The receptacles are convex to conic and honeycombed. The staminate flowers range from 20–30 and there are 19–43 pistillate flowers.

This and other "Baccharis" species are nectar sources for most of the predatory wasps, native skippers, and native flies in their ranges.

Naming

Subspecies
⤷ "Baccharis pilularis" subsp. "consanguinea" C.B.Wolf — primarily in coastal chaparral
⤷ "Baccharis pilularis" subsp. "pilularis" — sandy coastal bluffs and beaches in California.

Habitat

The plants are found in a variety of habitats, from coastal bluffs, oak woodlands, and grasslands, including on hillsides and in canyons, below 2,000 feet.

Coyote brush is known as a secondary pioneer plant in communities such as coastal sage scrub and chaparral. It does not regenerate under a closed shrub canopy because seedling growth is poor in the shade. Coast live oak, California bay, "Rhus integrifolia", and other shade producing species replace coastal sage scrub and other coyote bush-dominated areas, particularly when there has not been a wildfire or heavy grazing.

In California grasslands, it comes in late and invades and increases in the absence of fire or grazing. Coyote bush invasion of grasslands is important because it helps the establishment of other coastal sage species. However, establishment of coyote bush can be concerning because it also displaces highly biodiverse grassland habitat that are important to carbon storage and resilient to wildfires. After grassland restoration, coyote bush can be a major concern and plant invader that overtakes grassland habitat, especially if restoration activities are limited and nonperiodic.