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: Elm-Leaved Sumach

General Information

Rhus coriaria is a deciduous shrub that can grow up to 3 metres tall[].
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 in gardens[].
The plant is classified as 'Vulnerable' in the IUCN Red List of Threatened Species(2013)[].

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

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Range

S. Europe - Portugal and Spain to Greece, W. Asia - Turkey, the Crimea and the Levant to Tajikistan and Turkmenistan; Africa - Macaronesia, Algeria;

Habitat

Rocky places and waysides[, ], mainly on limestone[].

Properties

Conservation Status	Vulnerable
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	3.00 m
Pollinators	Bees
Cultivation Status	Wild

Cultivation Details

Rhus coriaria is not very cold-hardy, tolerating short-lived temperatures down to around -5°c when it is fully dormant, and is unlikely to succeed outdoors in any but the mildest parts of the temperate zone[, ]. Another report says that the plant is quite hardy and is often grown in British gardens[]. The young growth in spring is more tender, and can be damaged by late frosts.
Succeeds in a well-drained fertile soil in full sun[, ].
Unlike most members of this genus, this species is hermaphrodite[].
The form 'Humilior' from Italy is smaller growing[].
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[].

Edible Uses

The immature fruits are used as caper substitutes[, , , ]. Some caution is advised, see the notes above on toxicity.
The crushed fruit, mixed with Origanum syriacum, is a principal ingredient of 'Zatar', a popular spice mixture used in the Middle East[].
The seeds and fruits are used as a flavouring in many traditional dishes in Kurdistan, and as a spice in Anatolia[].

The seed is used as an appetizer in a similar manner to mustard[].

Medicinal

The leaves and the seeds are astringent, diuretic, styptic and tonic[, ]. They are used in the treatment of dysentery, haemoptysis and conjunctivitis[]. The seeds are eaten before a meal in order to provoke an appetite[].
Some caution is advised in the use of the leaves and stems of this plant, see the notes above on toxicity.

The fruits contain tannins and are astringent. The powdered fruits are eaten as a treatment for diarrhoea[]

Other Uses

The leaves and bark are rich in tannin[]. The leaves can be collected as they fall in the autumn and used as a brown dye or as a mordant[]. The fruit and bark are also used[]. The leaves contain 20 - 35% tannin[] and yield a yellow dye[].

The finely ground leaves and stems provide the dyeing and tanning agent 'sumac'[]. The shoots are cut down annually, near to the root, for this purpose[]. A fawn colour, bordering on green, is obtained and this can be improved with the judicious use of mordants[]. The cultivar 'Mesculino' is very rich in tannin, containing up to 35%[, ].

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[].

A black dye is obtained from the fruit[, ].
A yellow and a red dye are obtained from the bark[].

An extract of the leaves and stems is used as an ingredient in commercial cosmetic preparations as an antioxidant[].

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[]. 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[].