Species distinguishing characteristics:
- Evergreen shrub with glossy, alternate leaves
- Upper leaf surface often sticky with a heavy, fragrant resin
- Leaves have 3 main veins that extend from the base
- Clusters of white flowers along side branches and at tips
- Often grows in dense patches in open areas
- Shrubs or small trees with undivided, alternate leaves
- Clusters of small white or greenish flowers in leaf joints or stem tips
- Flowers have 4–5 sepals and stamens (pollen organs)
- Disk-shaped flowers attach by short-stalks, or stalkless
- Fruit is a juicy berry or a 3-celled capsule
- Grooved, thin-coated seeds
Evergreen shrub, 0.5–3 m tall, with erect and spreading stems. Often grows in dense patches from a single large taproot and a deep, spreading root system.
Leaves and stems:
Glossy, evergreen leaves have a heavy, spicy-resinous fragrance when crushed or wafted into the air on hot days. Alternate leaves, 3–10 cm long, have stalks, 3 main veins from the base, are curled, and are oval- to egg-shaped with finely toothed edges. On the upper surface, leaves are dark green, shiny, somewhat sticky with resin, and often bronze tinged. On the lower surface, leaves are sparsely gray-haired to velvety-haired; specimens in drier areas often have thicker velvet to prevent excess water loss. A pair of stipules (leaf-like appendages), each 1 mm long, attach to stems at leaf stalks.
Smooth, olive-green bark on younger twigs. Bark on older twigs becoming grayish-green to brown and furrowed with green.
Numerous tiny, creamy white flowers attach by stalks in round to pyramidal, branched clusters, up to 12 cm long, along the length of and at the tips of side branches. Fragrant flowers, 4 mm wide, are star-shaped with 5 slender, hood-shaped petals, 5 tiny sepals, 5 stamens (pollen organs), 3 stigmas (tip of a female organ), and a flat-lobed disk that contains the ovary.
Fruit is a glandular-sticky, 3-chambered capsule, 3–5 mm long, with a small crest on the back of each lobe. Each hardened lobe contains a single shiny seed that explodes when mature and ejects the seeds. The heat-resistant seeds appear to be capable of remaining dormant in the soil for approximately 200 years until stimulated to germinate by fire or other disturbances.
Moist to dry open forests, brushy sites, rocky slopes, and recently burned or disturbed areas such as roadsides and logged areas at low to subalpine elevations. Prefers full sun.
Small mammals and birds eat the seeds of snowbrush ceanothus. Its foliage provides year-round browse for mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus), bighorn sheep (Ovis canadensis), moose (Alces alces), and mountain goats (Oreamnos americanus). The nutrition content is high due to the ability of snowbrush ceanothus to fix nitrogen, which is deficient in most soils. Root nodules formed by soil bacteria (actinomycetes) enable the plant to absorb nitrogen from the air. Nitrogen-fixing plants can often colonize marginal soils that are inhospitable to many other plants. After a disturbance, this allows snowbrush ceanothus to form large, dense thickets that diminish in size as the canopy closes. The species’ ability to establish rapidly and its extensive root system make it excellent for reducing erosion and rebuilding the quality of depleted soils.
The dried leaves make a pleasant tasting, astringent tea that can be used as a caffeine-free black tea substitute. Kootenai tribes used the tea to treat tuberculosis. Other native tribes used a decoction of leaves for eczema, dandruff, and arthritis. Saponins, foam-producing compounds, in the flowers also make it useful for soap.