Ribes ambiguum

Ribes ambiguum is a small deciduous shrub in the Grossulariaceae family. It comes from temperate parts of eastern Sichuan in China. Its Japanese range includes Honshu, Kyushu, and Shikoku. Kew describes its form as a shrub or epiphytic subshrub. It reaches about 2 feet [0.6 metres] in height. It loses its leaves rather than keeping them through winter.

Its wild home differs from that of many garden shrubs. It often grows as an epiphyte on tree branches. There, its roots sit in damp moss above the ground. In gardens, it suits woodland edges and spots with dappled shade. It also grows in sun, though it prefers cool, sheltered sites. Shade is tolerated, but it reduces the fruit crop.

Flowers appear in May, and insects pollinate them. Each flower has both male and female parts. Seeds ripen from July through August. The green fruit reaches about half an inch across. People eat it fresh or cook it. The taste is sour rather than sweet. People gather and eat the fruit where the shrub grows wild. Plants For A Future gives its edible value two out of five. That source lists no known hazards, but gives no detailed safety assessment.

For garden soil, choose loam that holds moisture yet drains well. Soil of at least fair quality supports easy growth. The plant also accepts sandy ground and clay. It grows in mildly acid, neutral, or mildly alkaline soil. A soil rich in leaf matter suits its stated preference. Keep the root zone moist without losing good drainage. Plants For A Future lists USDA zones 5–9. It also reports cold tolerance near −20°C. The shrub can host a stage of white pine blister rust. Avoid planting it near pine trees for that reason.

Seed and cuttings offer ways to raise new plants. Sow fresh ripe seed in a cold frame in autumn. Stored seed needs three months of cold treatment before sowing. Keep young seedlings in a cold frame through their first winter. Plant them out in late spring the next year. Take half-ripe cuttings in July or August. Mature wood cuttings can be taken from November through February. No medicinal or other non-food uses are recorded in the supplied account.