Back to main Search Page

Rhus vernix - L.

Poison Sumach

Author	L.	Botanical references	11, 43, 200
Family	Anacardiaceae	Genus	Rhus
Synonyms	Rhus venenata - DC. Toxicodendron vernix - (L.)Kuntze.
Known Hazards	This plant contains toxic substances and skin contact with it can cause severe irritation to some people[11]. The sap is extremely poisonous[11]. The sap contains 3-N pentadecycatechnol. Many people are exceedingly sensitive to this, it causes a severe spreading dermatitis. The toxins only reach the skin if the plant tissues have been damaged, but even indirect contact can cause severe problems[200].
Range	Eastern N. America - Maine to Vermont and Ontario, south to Florida, Missouri and Louisiana.
Habitat	Wooded swamps, often inundated for part of the year[4, 43, 82].
Edibility Rating	0 (1-5)	Medicinal Rating	1 (1-5)

Physical Characteristics

A decidious Shrub growing to 3m.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires moist or wet soil.

Habitats

Woodland Garden; Sunny Edge; Dappled Shade; Bog Garden;

Edible Uses

None known

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Febrifuge; Miscellany; Skin.

Poison sumach has occasionally been used medicinally, though it is an extremely poisonous plant and great caution should be exercised. Any herbal use should only be undertaken under the supervision of a qualified practitioner. See also the notes above on toxicity. The plant has been used in the treatment of fevers, ague, ulcerated bladder, asthma and wasting diseases[257]. The plant has been used as a wash to treat foul ulcers[257].

Other Uses

Dye; Ink; Mordant; Oil; Varnish; Wood.

The leaves are rich in tannin. They can be collected as they fall in the autumn and used as a brown dye or as a mordant[169]. An oil is extracted from the seeds[4]. It attains a tallow-like consistency on standing and is used to make candles. These burn brilliantly, though they emit a pungent smoke[4]. An indelible black ink can be made from the sap[226]. A varnish is obtained from the sap, it is black, lustrous and durable[19, 82].The final product is toxic[226]. Wood - light, soft, coarse grained[82]. It weighs 27lb per cubic foot[235].

Cultivation details

Succeeds in a well-drained fertile soil in full sun[11, 200]. Requires a moist soil[14]. The young growth in spring can be damaged by late frosts. Plants have brittle branches and these can be broken off in strong winds[200]. Plants are also susceptible to coral spot fungus[11]. Plants in this genus are notably resistant to honey fungus[200]. Many of the species in this genus, including this one, are highly toxic and can also cause severe irritation to the skin of some people, whilst other species 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, 4]. The toxic species are sometimes separated into their own genus, Toxicodendron, by some botanists[200]. Dioecious. Male and female plants must be grown if seed is 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[200]. The stored seed also needs hot water treatment and can be sown in early spring in a cold frame[200]. 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, July/August in a frame[200]. Root cuttings 4cm long taken in December and potted up vertically in a greenhouse. Good percentage[78, 200]. Suckers in late autumn to winter[200].

Links

References

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[11] Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981
A classic with a wealth of information on the plants, but poor on pictures.

[14] Holtom. J. and Hylton. W. Complete Guide to Herbs. Rodale Press 1979 ISBN 0-87857-262-7
A good herbal.

[19] Stary. F. Poisonous Plants. Hamlyn 1983 ISBN 0-600-35666-3
Not very comprehensive, but easy reading.

[43] Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950
A bit dated but good and concise flora of the eastern part of N. America.

[78] Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948
A bit dated but a good book on propagation techniques with specific details for a wide range of plants.

[82] Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965 ISBN 0-486-20278-X
Two volumes, a comprehensive listing of N. American trees though a bit out of date now. Good details on habitats, some details on plant uses. Not really for the casual reader.

[169] Buchanan. R. A Weavers Garden. 0
Covers all aspects of growing your own clothes, from fibre plants to dyes.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. 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.

[226] Lauriault. J. Identification Guide to the Trees of Canada Fitzhenry and Whiteside, Ontario. 1989 ISBN 0889025649
Very good on identification for non-experts, the book also has a lot of information on plant uses.

[235] Britton. N. L. Brown. A. An Illustrated Flora of the Northern United States and Canada Dover Publications. New York. 1970 ISBN 0-486-22642-5
Reprint of a 1913 Flora, but still a very useful book.

[257] Moerman. D. Native American Ethnobotany 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.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Add a comment/link:

Discussion Monitor

To have posts to this page mailed to you enter your email address here:

(Your email address will not appear on the webpage or be passed on to third parties).