Rhus potaninii

Rhus potaninii, or Potanin's sumac, is a deciduous tree from China. It belongs to the cashew family, Anacardiaceae. Its native range includes central China and extends to Henan. It grows in woods and thickets on mountain slopes. Recorded sites lie at 2,950–8,200 feet [900–2,500 metres]. These habitats fall within temperate parts of China.

In gardens, it reaches 26–39 feet [8–12 metres] tall. Its spread reaches 13–26 feet [4–8 metres]. The crown has a rounded shape and bushy growth. It takes 20–50 years to reach its full size. The dark green leaves have seven to eleven leaflets. Each leaf can reach about 1.1 feet [0.35 metres] long. The leaves turn red in autumn, then fall. Summer brings hanging clusters of cream-white flowers. Round red fruits follow, with hairs on their surface. The fruits grow in clusters.

Grow this tree in full sun for strong autumn colour. It needs moist soil that lets excess water drain away. It accepts chalk, clay, loam and sand. Acid, neutral and alkaline soils all suit it. Both exposed and sheltered sites are listed as suitable. The RHS rates its hardiness as H6. This covers winter lows of about −20 to −15°C. Plants For A Future lists USDA zones 4–8. Growers can raise new plants from seed or semi-hardwood cuttings.

Its rounded crown suits a woodland garden canopy. The RHS also lists coastal and informal gardens as uses. Its red autumn leaves provide seasonal interest in these settings. The RHS places it among low-maintenance planting choices. Pests seldom cause trouble, according to the RHS. Honey fungus, coral spot and Verticillium wilt may affect it. Plants For A Future does not flag it as weedy.

Plants For A Future gives it no food-use rating. Its oil entry does not establish a clear edible use. Reports suggest sap may cause a rash in sensitive people. That source notes that these reports remain unconfirmed. The leaves contain tannin and can yield brown dye. They also serve as a mordant to help fix dyes. Seed oil thickens on standing and has served in candles. Those candles produce pungent smoke. Leaf galls provide a lasting black ink. Traditional medicine also uses insect-made leaf galls. Reported uses include treating bleeding, diarrhoea and wounds.