Plant of the Week
Rubber Rabbitbrush (Ericameria nauseosa (Pall. ex Pursh) G.L. Nesom & Baird)
By Sarah Malaby
Rubber rabbitbrush is also known as gray rabbitbrush, or chamisa. This perennial shrub is a member of the Aster family (Asteraceae) along with sagebrush, with which it is often found. Rubber rabbitbrush is highly variable, with several different subspecies located throughout the western United States. It is typically distinguished by having whitish to green flexible stems, felt-like matted hairs, and narrow, thread-like grayish-green alternate leaves. Shrubs are rounded and generally two to five feet tall, but can reach as high as seven feet. Flower heads are made up of 5 small, yellow, tubular flowers, and are arranged in dense, rounded or flat-topped clusters at the ends of the branches. Flowers bloom from August to October as other plants are fading, providing vivid color and a pollen source for insects late in the summer. The shrubs reproduce via an abundance of small, wind-dispersed seeds and can also sprout from the base.
Rubber rabbitbrush occurs as a dominant to minor component in many plant communities, ranging from arid rangelands to montane openings. It thrives in poor conditions, and can tolerate coarse, alkaline soils. Dense stands are often found on degraded rangelands, along roadsides, and in abandoned agricultural fields. The species is useful in soil stabilization and restoration of disturbed sites. The deep root system establishes quickly and plants produce large quantities of leaf litter, helping to bring nutrients to the soil surface from the deeper rooting profile. Rubber rabbitbrush is also gaining popularity as an ornamental; the white/gray foliage, abundant flowering, and tolerance for poor conditions makes it well suited for desert landscaping.
Native Americans reportedly used rabbitbrush as a yellow dye, to make a medicinal tea, and for chewing gum. The forage value of rubber rabbitbrush varies greatly among subspecies and ecotypes. In some locations, it can be an important browse species for mule deer, pronghorn, and jackrabbits during fall and winter. It also provides cover for mammals and small nesting birds. Livestock generally forage only lightly on this species and it is considered to be of little value to all classes of livestock.
The species name “nauseosa” refers to the smell given off when the leaves or flowers are crushed, described as pineapple-like by some and foul and rubbery by others. The common name refers to the rubber content in the sap, which varies by subspecies. Rabbitbrush was first tested as a source of high quality rubber during World War II. In recent decades, there has been renewed interest in its potential for production of rubber, resins, and other chemicals. Compounds in rubber rabbitbrush are being evaluated for nematocides, anti-malarial properties, and insect repellents. Rubber rabbitbrush has also been identified as a potential source of biomass and biocrude fuels.