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Anacardiaceae FAMILY

Rhus trilobata

Rhus trilobata

Edibility
3/5
Medicinal
2/5

Safety & 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[1, 2]. 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.

Cultivation Details

HabitDeciduous Shrub
Growth—

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[3]. 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[4, 5, 3]. Tolerant of a wide range of soils from clays to sands and even in nearly bare rock[6]. It prefers a slightly alkaline soil[3]. It produces its best fruit when grown close to moist ground[7]. Judging by the plants native habitat it should succeed in dry soils[PFAF]. Established plants are drought tolerant[3]. 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[3]. The plant generally resprouts freely from suckers if cut back or burned by fire[6]. A very variable species, several varieties are recognised. It is closely allied to Rhus aromatica[4]. Plants have brittle branches and these can be broken off in strong winds[5]. Plants are also susceptible to coral spot fungus[4]. Plants in this genus are notably resistant to honey fungus[5]. The foliage, especially when bruised, has a strong, skunk-like smell[6]. A dioecious species - both male and female forms must be grown if fruit and seed are required.

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[5]. 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[5]. 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[5]. Root cuttings 4cm long taken in December and potted up vertically in a greenhouse. Good percentage[8, 5]. Suckers in late autumn to winter[5]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Rhus+trilobata>

Pollinators

Bees

References

  1. [1]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  2. [2]A Modern Herbal. — Grieve. · Penguin · 1984 · ISBN 0-14-046-440-9 ↩︎Not so modern (1930's?) but lots of information, mainly temperate plants.
  3. [3]Fire Effects Information System — http://www.feis-crs.org/feis/ ↩︎An on-line information site with comprehensive information on over 1,100 species of plant. Mainly developed to supply information on the effects of fire on plants and animals, it also contains a wealth of other information on the plants
  4. [4]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]Plants Database — United States Department of Agriculture · http://plants.usda.gov/java/factSheet ↩︎An online database with an excellent collection of fact sheets about native N. American plants.
  7. [7]Edible Native Plants of the Rocky Mountains. — Harrington. H. D. · University of New Mexico Press · 1967 · ISBN 0-8623-0343-9 ↩︎A superb book. Very readable, it gives the results of the authors experiments with native edible plants.
  8. [8]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  9. [9]A Field Guide to N. American Edible Wild Plants. — Elias. T. and Dykeman. P. · Van Nostrand Reinhold · 1982 · ISBN 0442222009 ↩︎Very readable.
  10. [10]Trees of Central Texas. — Vines. R. A. · University of Texas Press · 1987 · ISBN 0-292-78958-3 ↩︎A good concise guide, it gives details of habitats and some of the uses of trees growing in Texas.
  11. [11]Early Uses of Californian Plants. — Balls. E. K. · University of California Press · 1975 · ISBN 0-520-00072-2 ↩︎A nice readable book.
  12. [12]Common Edible and Useful Plants of the West. — Sweet. M. · Naturegraph Co. · 1962 · ISBN 0-911010-54-8 ↩︎Useful wild plants in Western N. America. A pocket guide.
  13. [13]Edible and Useful Wild Plants of the United States and Canada. — Saunders. C. F. · Dover Publications · 1976 · ISBN 0-486-23310-3 ↩︎Useful wild plants of America. A pocket guide.
  14. [14]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  15. [15]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.
  16. [16]A Weavers Garden — Buchanan. R. · McGraw-Hill Contemporary · 1987 · ISBN 0934026289 ↩︎Covers all aspects of growing your own clothes, from fibre plants to dyes.
  17. [17]Dictionary of Economic Plants. — Uphof. J. C. Th. · Weinheim · 1959 · ISBN - ↩︎An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.
  18. [PFAF]Plants for a Future — pfaf.org ↩︎