Rhus potaninii

Family: Anacardiaceae

What it is like

Rhus potaninii is a deciduous Tree growing to 12 m (39ft) by 8 m (26ft). See above for USDA hardiness. It is hardy to UK zone 5 and is not frost tender. It is in flower in June, and the seeds ripen from August to October. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Bees. The plant is not self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Height (m): 12

Where it is found

Thickets and in woods on slopes at elevations of 900 - 2500 metres.

E. Asia - C. and W. China.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Oil: Oil

Medicine

Rating: 2

An excrescence produced on the leaf by an insect Melaphis chinensis or M. paitan is antiseptic, astringent and haemostatic. It is used in the treatment of persistent cough with blood, chronic diarrhoea, spontaneous sweating, night sweats, bloody stool, urorrhoea and bloody sputum. It is used applied externally to burns, bleeding due to traumatic injuries, haemorrhoids and ulcers in the mouth.

Antiseptic: Preventing sepsis, decay or putrefaction, it destroys or arrests the growth of micro-organisms.

Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.

Haemostatic: Controls internal bleeding.

Other

Rating:

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. An indelible black ink is obtained from galls on the leaves. The report does not say if the galls are used before or after the insect leaves them.

Dye: Plants that provide dyes.

Ink: Plants that can be used as an ink.

Mordant: Used for making a dye more permanent, it also affects the colour of the dye.

Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.

How it is grown

Succeeds in a well-drained fertile soil in full sun. The young growth in spring can be damaged by late frosts. A very ornamental plant, but it rarely flowers in Britain. This species is very closely related to R. punjabensis. 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. 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. The toxic species are sometimes separated into their own genus, Toxicodendron, by some botanists. Dioecious. Male and female plants must be grown if seed is required.

Propagating it: 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, July/August 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.

Best place to grow: Woodland Garden Canopy; Secondary;

Habit: Tree

Hardiness: 4-8

Growth:

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Moist

Things to keep in mind

There are some suggestions that the sap of this species can cause a skin rash in susceptible people, but this has not been substantiated. See also notes in 'Cultivation Details'.

Its other names

Local names

Synonyms

R. henryi. R. sinica. non Diels.