Rhus ambigua

Family: Anacardiaceae

What it is like

Rhus ambigua is a deciduous Climber. See above for USDA hardiness. It is hardy to UK zone 7 and is not frost tender. 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 can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 0

Where it is found

Mountainous woods all over Japan.

E. Asia - Japan.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Oil: Oil

Medicine

Rating: 0

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. A natural lacquer is obtained by tapping the stem.

Dye: Plants that provide dyes.

Lacquer: A type of varnish.

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. A woodland plant in its native habitat, it should also succeed in some shade. The young growth in spring can be damaged by late frosts. Plants have brittle branches and these can be broken off in strong winds. Plants are also susceptible to coral spot fungus. 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. The toxic species are sometimes separated into their own genus, Toxicodendron, by some botanists. Plants in this genus are notably resistant to honey fungus. 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. 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 Sunny Edge; Dappled Shade; Shady Edge;

Habit: Climber

Hardiness: 6-9

Growth:

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

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

This plant contains toxic substances that can cause severe irritation to some people. All parts of the plant contain resinous phenolic compounds known as urushiols. Direct contacr with the plant, exposure to smoke or fumes from a burning plant or even contact with pets or animals that have touched the plant can cause severe allergic dermatitis in some individuals. There is usually a latent period of about 12 - 24 hours from the moment of contact, this is followed by a reddening and severe blistering of the skin. Even plant specimens 100 or more years old can cause problems.

Its other names

Local names

Synonyms

R. orientalis. R. toxicodendron hispida. Toxicodendron orientale. T. radicans orientale. (Greene.)Gi