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: Lemonade Berry

General Information

Rhus integrifolia is usually an evergreen shrub, forming an impenetrable thicket of growth perhaps 2 - 5 metres tall. It sometimes becomes more tree-like, growing up to 10 metres tall with a short, thick trunk perhaps 60 - 90cm in diameter beneath a wide crown of straggling branches that often recline upon the ground and form roots[, ].
The plant is harvested from the wild for local use as a food and a source of materials. A very ornamental plant, especially when in flower and, later, in fruit[].

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

South-western N. America - California, northern Mexico (Baja Norte)

Habitat

Ocean bluffs, canyons and dry places below 800 metres[], in sandy sterile soil[]. Often forming close, impenetrable thickets[].

Properties

Edibility Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	2.00 m
Pollinators	Bees
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Rhus integrifolia is not very cold-hardy, tolerating occasional falls in temperature to around -5°c when it is fully dormant. It requires hot summers if it is to thrive, since this ensures that its new growth is fully developed and ripened - in areas with cool summers it will be even more cold-sensitive[]. Older plants become somewhat hardier and so it is worthwhile growing them on for a few years in pots with some winter protection (such as a cold greenhouse) in areas towards the edge of their hardiness[]. Some 4 year old plants were cut back to the base by temperatures below -5°c on our Cornish trial grounds, but they resprouted from the base in early summer[]. The young growth in spring is also very cold-sensitive and can be damaged by late frosts.
The plant succeeds in a well-drained fertile soil in full sun[, ]. Succeeds in a hot dry position.
Plants usually form thickets in the wild[].
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[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

Fruit - raw or cooked[, , , ]. The fruit is covered with a pleasant acid-tasting exudation that can be sucked[, ]. Individual fruits are quite small, up to 10mm in diameter[], with very little flesh, but it is produced in fairly large panicles and so is easily harvested. When soaked for 10 - 30 minutes in hot or cold water it 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 leaves have been chewed to assuage thirst[].

The roasted fruit is a coffee substitute.

Medicinal

None known

Other Uses

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[].

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 heartwood is salmon-pink in colour, becoming lemon-yellow near the thin band of white apwood. The wood has a fine grain and is hard, heavy and strong. It takes a fine polish[, ].
The wood is valued and largely used as a fuel[, ].

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[]. Prick out the seedlings into individual pots when they are large enough to handle. It might be wise to grow the plants on in pots for a few years before planting out - see notes in 'Cultivation Details'[].
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[].