Common Name: Spiny Horsebrush

General Information

Tetradymia spinosa is a deciduous perennial plant with stems that become more or less woody. Growing from a woody rootstock and producing rhizomes up to 30cm long, the plant produces one or more erect, very spiny, much-branched stems 10 - 100cm tall, often forming a small colony[, ]. The spines on the typical variety are 5 - 15mm long, but in the variety longispina they can be up to 50mm long[].
The plant is harvested from the wild for local medicinal use.

Known Hazards

Toxicity of this species is low[], though in general all species of Tetradymia should be considered toxic to grazing animals[]. Symptoms include swollen, engorged liver with severe fatty changes and low grade nephritis (inflammation of nephrons) of the kidney along with haemorrhaging of the sub-skin and organ linings. Abortions may also occur[].

Botanical References

Range

Western N. America - Oregon to Montana, south to California and New Mexico

Habitat

Usually sandy soils of alkali sinks, shadscale scrub, pinyon-juniper woodlands; at elevations from 800 - 2,400 metres[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	0.60 m
Pollinators	Bees, Lepidoptera, Insects
Cultivation Status	Wild

Cultivation Details

Tetradymia spinosa is native to the semi-arid regions of southwestern N. America, growing in areas where the mean annual precipitation ranges from 200 - 350mm[]. Summer temperatures can often exceed 40°c and winters can be cool to cold[].
The plant grows in the wild on shallow to deep soils with clay and loam textures and a pH in the range 6.5 - 8.2[]. Established plants are very drought tolerant, shedding their leaves in times of stress[].
Plants are usually top-killed by fire, but resprout freely from the roots afterwards[].

Edible Uses

A decoction of the plant is used as an external medicine[]. No more information is given.

Medicinal

None known

Agroforestry Uses:

Within its native range, spiny horsebrush helps stabilize soil on erodible desert sites and provides critically needed ground cover on dry sites that are otherwise often sparsely vegetated[].

Other Uses

The sharp spines were used as piercing instruments[].

Propagation

Seed - it probably benefits from 4 - 6 weeks of pre-chilling prior to sowing[]. Sow seed in containers in a light position - it should be only lightly covered with soil, but care should be taken to make sure the soil is not overwatered, nor does it dry out. Prick out the seedlings into individual pots when large enough to handle and grow on until large enough to plant out.