
Rhus microphylla
Rhus microphylla
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
Rhus microphylla is native to arid and semi-arid regions of southern N. America, where it ca be found at elevations up to 1,800 metres. Temperatures can range from up to 40°c in the summer, falling sometimes below freezing in the winter. Mean annual rainfall can range from 76 -- 406mm[3]. The plant only succeeds outdoors in the milder regions of the temperate zone, and also requires hot summers in order to ripen the new growth, in cooler regions the wood does not fully ripen and then is much more sensitive to cold damage. The young growth in spring is also very sensitive can be damaged by late frosts[PFAF]. Succeeds in a well-drained fertile soil in full sun[4, 5]. Found in the wild on soils developed from sandstone, limestone, and granite[3]. 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]. Many of the species in this genus are highly toxic and can also cause severe irritation to the skin of some people, whilst other species such as this one are not poisonous. It is relatively simple to distinguish which is which, the poisonous species have axillary panicles and smooth fruits whilst non-poisonous species have compound terminal panicles and fruits covered with acid crimson hairs[1, 2]. The toxic species are sometimes separated into their own genus, Toxicodendron, by some botanists[5]. 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[6, 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+microphylla>
Pollinators
Bees
References
- [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]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]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]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]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]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.
- [7]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.
- [8]Food Plants of the N. American Indians. — Yanovsky. E. · U.S. Depf of Agriculture. · ISBN - ↩︎A comprehensive but very terse guide. Not for the casual reader.
- [9]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.
- [10]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
- [11]A Weavers Garden — Buchanan. R. · McGraw-Hill Contemporary · 1987 · ISBN 0934026289 ↩︎Covers all aspects of growing your own clothes, from fibre plants to dyes.
- [PFAF]Plants for a Future — pfaf.org ↩︎