Attract wildlife and encourage a rare ecosystem with drought-hardy, sun-loving antelope brush
British Columbia is Canada’s most biologically diverse province with more species and ecosystems than anywhere else. Included among these is one of the rarest ecosystems in the country: the antelope brush ecosystem of the hot and dry interior desert landscapes. Many rare animal species and plants are associated with the ecosystem such as the burrowing owl and a butterfly, Behr’s hairstreak, which cannot survive without the antelope brush as food. Antelope brush (Purshia tridentata) is a tough and attractive plant of the Rose family well suited to warm dry gardens.
Antelope brush (also known as bitterbrush, bitter bush and antelope-bush) stands to 1 to 3 m (40 to 120 in.) tall as a mass of numerous rigid erect stems. Young twigs are notably covered in woolly hairs and older branches have grey or brown bark. As the shrub matures it may develop a gnarled and twisted form with some branches creeping on the ground. This shrub is notable for its extremely long tap root which may extend to 5.5 m (about 18 ft.) deep. The roots also fix nitrogen, improving the fertility of the soil.
Grayish woolly hairs and a rolled under edge are good signs that the shrub has strong adaptations to heat and drought.
A bush in bloom makes a very striking display. Numerous bright-yellow flowers cover the stems in the spring (April to June). Five egg- to spoon- shaped petals surround a mass of about 25 stamens and a single ovary. There is a glandular and hairy calyx below the petals.
Antelope brush may not be well known as a garden plant but it is widely used in the restoration of dry-land habitats of interior western North America. It is recommended as an ornamental for the water-wise garden, for use as hedging and as an specimen plant. Despite its sometimes unruly natural form, this species can be trimmed into neat shapes and kept at a manageable size. It grows slowly so that the attention required is not great. Plants are most easily raised from fall sown seeds which germinate readily in the spring. It can also be propagated from layering the lower branches on the ground, and covering them with soil until roots form.
Antelope brush had several medicinal and other indigenous uses throughout its North American distribution. Roots were used to make an infusion for lung problems and coughs. A poultice from the plant was useful for skin complaints. Chewing the leaves was supposed to bring good luck during hunting. The outer seed coat yields a purple dye.
This species is widely known for its wildlife and habitat values. It provides excellent browse for deer, California bighorn sheep, rodents such as mice, and birds, thus making it a potential magnet for wildlife in the interior garden. Ants love it too, creating stashes of the seeds. If you have a big deer population in your neighbourhood, you will have to protect young plants. Climate modelling studies carried out by the Royal BC Museum suggest that the species could grow well beyond its current range as the climate is changing. So gardeners in the north Okanagan and in the Kamloops area might consider this species. It can also be grown in coastal gardens but requires a very warm well-drained site.
If you are interested in water-wise gardening, attracting wildlife and in encouraging rare ecosystems and species, you might consider antelope brush for your southern interior garden or property.
Purshia tridentata (antelope brush) is hardy to zone 5
An expert on native plants, Richard Hebda is curator of Botany and Earth History at the Royal British Columbia Museum in Victoria.