Parthenocissus tricuspidata aka Boston Ivy

Parthenocissus tricuspidata, or Boston ivy, is a woody vine. It belongs to the grape family, Vitaceae. Its native range spans temperate parts of eastern Asia. This includes China, Japan, and the southern Russian Far East. It is not related to English ivy. This fast grower sheds its leaves each year. Garden heights range from 30–50 feet [9–15 metres]. Some sources report 60 feet [18 metres]. Spread varies greatly, and may exceed 26 feet [8 metres].

Short, branched tendrils end in pads that grip surfaces. These let the vine climb walls without added support. Young twigs are thin and pale red-brown. Smooth gray-brown bark bears raised, corky lenticels. Leaves grow in an alternate pattern along the stems. Most have three lobes and coarse teeth along their edges. Young leaves may instead have three separate leaflets. The upper leaf surface is glossy and dark green. Small hairs grow along the veins beneath. Leaves turn red or purple as autumn cools. Some stay on until late autumn or early winter.

Small, pale green to green-white flowers hide beneath the leaves. Sources place flowering in June or from May through August. The flowers draw bees but add little garden show. Dark blue-black berries follow on red stalks. They ripen in autumn and show after leaves fall. Birds eat them through autumn and winter. Dense stems and leaves can also shelter bird nests.

Boston ivy grows in sun, part shade, or full shade. RHS favors shaded sites for strong autumn leaf color. It accepts sand, loam, clay, and a broad pH range. Fertile soil with good drainage suits it well. It prefers moist soil but can withstand drought. Sources list USDA zones 4–8 and UK rating H5. It needs little care, though pruning keeps growth in bounds. It can cover walls, fences, trellises, or bare ground. On slopes, it can help hold soil in place.

Its grip can damage paint, shingles, and parts of buildings. Pads may leave marks and prove hard to remove. Growth can swamp smaller plants or overtake trees. It can escape gardens; Connecticut reports invasive behavior. Serious pest and disease trouble is not usual. Leaf spots, mildew, canker, wilt, and honey fungus may occur. Pests include beetles, scale, leafhoppers, mites, and vine weevils. PFAF records sweet spring sap as a sugar substitute. However, RHS warns of harm to people and pets if eaten. It also warns that contact can irritate skin.