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: Lemon Sumach

General Information

Rhus aromatica is a straggling to upright deciduous shrub, rarely becoming more tree-like; it usually grows 50 - 200cm tall, sometimes reaching 250cm. Suckering at the roots, the plant can form dense thickets 3 metres or more across[, ].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is grown as a ground cover, soil stabilizer and to rehabilitate disturbed sites, and is also grown as an ornamental, where it is valued especially for its autumn colouring[].

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

Eastern N. America - Ontario to Quebec, south to Texas and Florida.

Habitat

Dry rocks, sands and open woods[], often on limestone outcrops[]. Found in a range of sites, including open rocky woodlands, valley bottoms, lower rocky slopes, and roadsides[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	1.20 m
Pollinators	Bees
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Rhus aromatica is a very cold-hardy plant, able to tolerate temperatures down to around -25 to -35°c when fully dormant[, ]. The young growth in spring, however, is much more tender and can be damaged by late frosts.
Succeeds in a well-drained fertile soil in full sun and in partial shade[, , ]. Tolerates poor soils[, ]. Established plants are drought resistant, and also tolerate seasonal inundation of the soil[, ].
Top-growth of individual plants may live about 20 --30 years; the rootstock can live substantially longer through the many suckers it can produce[].
This species is a low suckering shrub[]. There is a specially low growing form, var. arenaria, that is found growing on sand dunes in the mid-west of N. America[].
A polymorphic species[].
Plants are susceptible to coral spot fungus[]. Plants have brittle branches that are easily damaged in very strong winds[]. Plants in this genus are notably resistant to honey fungus[]. This species transplants easily[].
The plant has an offensive smell[]. Or, to go by another nose, the bruised leaves emit a delicious resinous scent[].
Individual plants can bear both bisexual and unisexual flowers[].

Edible Uses

Fruit - raw or cooked[, ]. When soaked for 10 - 30 minutes in hot or cold water 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. The fruit can also be dried and ground into a powder then mixed with corn meal and used in cakes, porridges etc[]. Individual fruits are quite small, around 5 - 7mm in diameter, with very little flesh, but they are produced in clusters and are easily harvested[, ].

The ripe fruits are dried and used in teas[].

Medicinal

The leaves are astringent and diuretic[, ]. They were used in the treatment of colds, stomach aches and bleeding[].

The root bark is astringent and diuretic[, ]. An infusion can be used in the treatment of diarrhoea, dysentery. Used externally, it is used to treat excessive vaginal discharge and skin eruptions and also as a gargle for sore throats[]. Its use is contraindicated if inflammation is present[]. The root is harvested in the autumn and dried for later use[].

The fruits are astringent and diuretic[]. They have been chewed in the treatment of stomach aches, toothaches and gripe[] and used as a gargle to treat mouth and throat complaints[]. They help reduce fevers and may be of help in treating late-onset diabetes[].

The plant (part not specified) is used in homeopathic remedys to treat renal and urinary infections, especially diabetes, and other problems related to the urinary system[].

Some caution is advised in the use of the leaves and stems of this plant, see the notes above on toxicity.

Agroforestry Uses:

Rhus aromatica is a pioneer species, establishing rapidly from seed after heavy disturbance, particularly fire, and creating conditions suitable for successional species[, ].
The plant has an extensive, shallow, suckering root system and is sometimes planted to provide ground cover and to prevent soil erosion, especially on banks and eroded or poorer soils[, , , ].

Other Uses

The leaves are rich in tannin (up to 25%) and can be collected as they fall in the autumn then used as a brown dye or as a mordant[]. The bark is also a good source of tannin[].
A yellow dye can be obtained from the root[].

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 split stems are used in basket making[, , ].

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[].