Rhus trilobata closely resembles Rhus aromatica and is often treated as part of the latter[].
There has been considerable uncertainty amongst botanists as to the best way of treating the genus Rhus, with some viewing it in a strict sense as comprising of around 35 species and electing to separate the other species into several distinct genera; whilst others prefer to view the genus in a looser sense being comprised of perhaps 250 species grouped into several subgenera. The genus is treated here in its strict sense, with many other species that have at times been included here being moved to the genera Cotinus, Searsia and Toxicodendron.

Common Name: Skunk Bush

General Information

Rhus trilobata is an erect to spreading, deciduous shrub with a dense crown; it usually grows from 50 - 250cm tall, though in its most favourable habitats it can reach 360cm. The plant only occasionally forms suckers, though in the event that the top growth is damaged, it can sprout freely[, ].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is sometimes grown as an ornamental, valued especially for its autumn leaf display[].

Known Hazards

The genus Rhus is being treated in its strict sense here, so it excludes the many species with highly toxic and irritant sap (these are included in Toxicodendron). Although the two genera are very similar, it is relatively simple to distinguish which is which, the poisonous species (Toxicodendron) have axillary panicles and smooth fruits whilst non-poisonous species (Rhus) have compound terminal panicles and fruits covered with acid crimson hairs[, ].
Whilst the genus Rhus in this treatment is generally seen as having a non-toxic sap there are some suggestions that the sap of some species in the genus (including this one) can cause a skin rash in susceptible people.

Botanical References

,

Range

Western and central N. America - Alberta and Saskatchewan, south to California and Texas, through western Mexico to Colima

Habitat

Foothills, canyons, slopes etc, usually on dry rocky soils[] and especially on limestone outcrops[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	1.80 m
Pollinators	Bees
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Rhus trilobata prefers a mean annual rainfall within the range 250 - 500mm, though is adapted to a wide range of climates. It is known to thrive in areas where the average monthly temperature of the coldest month can be as low as -11°c and also where the average monthly temperature of the hottest month can be 26°c[]. The young growth in spring is not very cold tolerant and can be damaged by late frosts.
Succeeds in most well-drained moderately fertile soils, preferably in full sun but tolerating light shade[, , ]. Tolerant of a wide range of soils from clays to sands and even in nearly bare rock[]. It prefers a slightly alkaline soil[]. It produces its best fruit when grown close to moist ground[]. Judging by the plants native habitat it should succeed in dry soils[]. Established plants are drought tolerant[].
The plant is said to have a low fruit and seed production. It was estimated that only 5 - 15% of the flowers in a North Dakota shrub community actually produced fruit. Branches from 6 - 10 years of age produced the most viable fruit[].
The plant generally resprouts freely from suckers if cut back or burned by fire[].
A very variable species, several varieties are recognised. It is closely allied to Rhus aromatica[].
Plants have brittle branches and these can be broken off in strong winds[]. Plants are also susceptible to coral spot fungus[]. Plants in this genus are notably resistant to honey fungus[].
The foliage, especially when bruised, has a strong, skunk-like smell[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

Fruit - raw or cooked[, , , , , ]. The fruit can be eaten fresh, dried, mixed with cornmeal or made into a jam[]. When soaked for 10 - 30 minutes in hot or cold water it makes a very refreshing lemonade-like drink (without any fizz of course)[, , , ]. The mixture should not be boiled since this will release tannic acids and make the drink astringent. Individual fruits are quite small, around 6mm in diameter and with very little flesh, but they are produced in clusters and are easily harvested[, ].

Medicinal

Skunk bush was employed medicinally by several native North American Indian tribes, who valued it especially for its astringent qualities and used it to treat a range of complaints[]. It is little, if at all, used in modern herbalism. Due to its potentially toxic nature, it should be used with some caution and preferably only under the supervision of a qualified practitioner.

The fruit is analgesic, astringent and stomachic[]. It has been eaten as a treatment for stomach problems and grippe[]. The dried berries have been ground into a powder and dusted onto smallpox pustules[]. The fruit has been chewed as a treatment for toothache and also used as a mouthwash[]. A decoction of the fruit has been used as a wash to prevent the hair falling out[].

The leaves are astringent, diuretic, emetic and haemostatic[]. An infusion of the leaves has been used in the treatment of head colds[]. A decoction of the leaves has been drunk to induce impotency as a method of contraception[]. A poultice of leaves has been used to treat itches[].

An infusion of the bark has been used as a douche after childbirth[]. The bark has been chewed, and the juice swallowed, as a treatment for colds and sore gums[].

A decoction of the root bark has been taken to facilitate easy delivery of the placenta[].

The roots have been used as a deodorant[]. The buds have been used on the body as a medicinal deodorant and perfume[].

Agroforestry Uses:

The plant is useful for windbreaks and shelterbelts and, because of its strong, shallow and spreading root development, it has been found useful for erosion control[]. It survives on untreated mine spoils and has been planted in restoration projects on phosphate mine spoil sites[, ].

Other Uses

The leaves are rich in tannin. They can be collected as they fall in the autumn and used as a black to brown dye or as a mordant[, ]. The fruits can also be used as a mordant[].

A yellow dye is obtained from the twigs[]. black dye can be obtained when the twigs are mixed with pine gum[].
A red-brown dye can be made from the bark and leaves[].
A pink-tan dye can be made from the fruit[].

The ashes of the plant can be used as a mordant to fix dyes[].

An oil is extracted from the seeds[]. It attains a tallow-like consistency on standing and is used to make candles. These burn brilliantly, though they emit a pungent smoke[].

The roots have been used as a perfume and deodorant[]. The buds have been used on the body as a medicinal deodorant and perfume[].

The leaves have been rubbed on the body as an insect and snake repellent[]. Some caution should be employed here, see the notes above on toxicity[].

The branches are tough and slender, they are stripped of their bark and split into several strands then used in basket making[, , , , , ]. The pliable young stems can be woven with grass stems into durable baskets that hold water[].

Propagation

Seed - best sown in a cold frame as soon as it is ripe. Pre-soak the seed for 24 hours in hot water (starting at a temperature of 80 - 90c and allowing it to cool) prior to sowing in order to leach out any germination inhibitors[]. This soak water can be drunk and has a delicious lemon-flavour. The stored seed also needs hot water treatment and can be sown in early spring in a cold frame[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings of half-ripe wood, 10cm with a heel, mid summer in a frame[].
Root cuttings 4cm long taken in December and potted up vertically in a greenhouse. Good percentage[, ].
Suckers in late autumn to winter[].