Antelope Bitterbrush (Tridentata)

The Antelope Bitterbrush (Tridentata) is generally described as a perennial shrub. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the early spring, with fruit and seed production starting in the spring and continuing until summer. Leaves are not retained year to year. The Antelope Bitterbrush (Tridentata) has a long life span relative to most other plant species and a moderate growth rate. At maturity, the typical Antelope Bitterbrush (Tridentata) will reach up to 6 feet high, with a maximum height at 20 years of 6 feet.

The Antelope Bitterbrush (Tridentata) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, seed. It has a slow ability to spread through seed production and the seedlings have medium vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -36°F. has high tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Bitterbrush is recommended for restoring depleted rangelands, burned areas, mined lands, and other distributed sites in the Intermountain West. It is mainly valuable for improving forage production and quality for big game on fall and winter ranges. Material available commercially has been selected for seedling vigor, productivity, upright growth form, palatability, forage availability, seed production and retention of over-wintering leaves.

Historic Native American Uses: Western Indian groups used leaf poultice or wash for itches, rashes, insect bites, chickenpox, and measles. Leaf tea was used as a general tonic and for colds, pneumonia, liver disease, to expel worms, and as an emetic and laxative for stomach ache and constipation. Twigs, leaves, and berries were used as a laxative. Root teas were used for coughs, lung and bronchial infections, fever, and to facilitate delivery of placenta.

General Characteristics

General: Rose Family (Rosaceae). Mature plants are large, leafy perennial shrubs with few basal stems. They have spreading crowns, heavy lateral spur production, and long ascending leaders. The average height is 8 feet with a 10-foot crown. Floral and vegetative morphology is typical for bitterbrush, with little introgression from Stansbury cliffrose (Purshia stansburiana), an unpalatable related species native to the Southwest.

Flowers are small, varying from white to yellow, and produced profusely along each leader. The seeds are large for the species—15,500 per pound. They are about one-fourth inch long and obovate. Seeds, stems, and leaves are nontoxic.

Individual bitterbrush plants exhibit considerable variation for growth form. Bitterbrush’s growth forms vary from a uniform, erect growth habit to more decumbent, layering forms. Users are encouraged to consider the various forms of bitterbrush in choosing a strain best suited to their needs.

Required Growing Conditions

Bitterbrush is found in the intermountain west including Arizona, British Columbia, California, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. Bitterbrush does not occur west of the Cascade Mountains in the northwest United States. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Adaptation Bitterbrush is associated with big sagebrush (Artemisia tridentata) and rabbitbrush (Chrysothamnus sp.). It occurs naturally on dry lake beds, alluvial fans or terraces, and low foothills. It occurs in soils that are deep, gravelly, loamy coarse sands derived from granite, with pH ranging from 6.0 to 7.0.

Tests have shown that bitterbrush has high potential for use on deep, coarse, well-drained, neutral to slightly acidic soils in areas that have 12-24 inches of annual precipitation. It is not well-adapted to basic, fine-textured, or poorly drained soils. Bitterbrush has performed well at sites in eastern Oregon, central and southern Idaho, northern California, and western Nevada at elevations of 3,000 to 6,000 feet. It performs best on sites that support bitterbrush-grass, basin big sagebrush-grass, mountain brush, and ponderosa pine-bitterbrush plant communities.

Bitterbrush has also performed adequately in Utah. Another strain, however, is being developed for the eastern part of the area of adaptation and a layering form for very sandy sites that are subject to blowing.

Cultivation and Care

On rangeland sites, bitterbrush should be seeded in late fall or winter to permit field stratification. Pretreatment with hydrogen peroxide is required to break dormancy for spring seeding. Seedlings are susceptible to late frosts. Plants develop very slowly and must be protected from competition during the first two seasons. Recommended seeding rates are 1 to 3 pounds of pure live seed per acre. Bitterbrush seedlings are often transplanted on critical sites. In such castes, moisture must be adequate to ensure survival in the first year. One-year-old bare-root or containerized seedling stock, 6 to 24 inches tall, is recommended.

Several insects and diseases are known to damage the foliage, seed, and seedlings of bitterbrush, and are more or less susceptible than other species. High-density populations of grasshoppers can destroy seedlings.

General Upkeep and Control

Bitterbrush is used by big game and livestock during all seasons and remains productive despite heavy browsing. Stand conditions generally deteriorate however, when annual use exceeds 60 percent of the annual growth. Bitterbrush is not fire-tolerant and re-sprouts only infrequently following burning.

Pests and Potential Problems A number of insects and diseases are known to damage the foliage, seed, and seedlings of bitterbrush. Individual plants growing in uniform garden plots of bitterbrush have not been observed to be more susceptible to damage by insects or diseases than other accessions of the species. Grasshoppers in high densities have damaged or destroyed seedlings. A beneficial organism associated with antelope bitterbrush is the nitrogen-fixing endophyte Frankia purshiae.

Seeds and Plant Production Mature seed must be harvested with 3 to 10 days of ripening because it shatters quickly after reaching maturity. Seed may be harvested into canvas hoppers or aluminum seed collection trays positioned under the shrubs prior to seed fall. Seed collection and orchard maintenance are simplified by the upright growth form.

A 3.6 to 3.6 m to 4.9 x 4.9 m (12 x12 ft to 16 x 16 ft) spacing is recommended for antelope bitterbrush seed orchards. Plants in wildland stands reach full seed production in 8 to 20 years. With appropriate cultural practices, this period may be reduced to about 5 years for seed orchards. Nine-year old shrubs grown at 2.4 m (8 ft) spacings without irrigation or other cultural treatments at the Boise Shrub Garden, produced 118 g (0.26 lbs) of seed per shrub or 199 kg/ha (177 lbs/acre).

Seed is easily cleaned to a purity of 95 percent using a two-screen fanning mill and a barley debearder. Shriveled black seed is nonviable and should be separated with the chaff. Seeds of bitterbrush are relatively large, averaging 34,507 seeds/kg (15,685 seeds/lb) for cleaned seed, with germination averaging about 84 percent. Seeds of bitterbrush remain viable for 15 years or more in open storage.

On rangeland sites antelope bitterbrush is normally seeded in late fall or winter to permit field stratification of the seed. Pretreatment with hydrogen peroxide is required to break dormancy for spring seeding. Seedlings are susceptible to late frosts. Plants develop very slowly and must be protected from competition during the first two seasons. Recommended seeding rates are 1.2 to 3.3 kg/ha (1 to 3 lbs/acre). Bitterbrush may be established on critical sites by transplanting.

Plant Basics
Growth Rate Moderate
General Type Shrub
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Long
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Early Spring
Displays Fall Colors No
Shape/Growth Form Multiple Stem
Drought Tolerance High
Shade Tolerance Intermediate
Height When Mature 6
Vegetative Spread None
Flower Color White
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Spring Summer
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Seed
Moisture Requirements Low
Cold Stratification Required Yes
Minimum Temperature -36
Soil Depth for Roots 20
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability Yes
Responds to Coppicing No
Growth Requirements
pH Range 5.6–8.4 pH
Precipitation Range 8–8 inches/yr
Planting Density 1212–2728 indiv./acre
Soil Textures Coarse, Medium
Soil Depth for Roots 20
Minimum Frost-Free Days 100 day(s)
Salinity Tolerance None
CaCO3 Tolerance High
Sustainability & Use
Leaf Retention No
Palatability High
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA