Apios americana aka Apios

Apios americana is a perennial vine in the bean family. Its names include American groundnut, potato bean, and hopniss. It grows wild from eastern Canada through central and eastern America. It lives in wet thickets, marshes, and stream banks. It also grows in damp woods and low ground. Fleshy tubers beneath the soil send up twining shoots. The vine loses its leaves and dies back in autumn.

Garden vines reach 10–15 feet [3–4.6 metres] with support. Reports range from 5–8 feet [1.5–2.5 metres] to 16 feet [4.9 metres]. Spread can reach 5 feet [1.5 metres], though RHS gives much less. Green, hairy stems wind around shrubs or other supports. The green leaves grow in an alternate pattern. Each pinnate leaf has five to seven pointed leaflets. These have smooth edges and may have hairs beneath.

Pea-like flowers form tight racemes where leaves meet the stems. Their shades range from reddish purple to pinkish brown. Some have pale brown outsides and dark red-brown centres. The flowers have a scent and bloom from June to August. RHS also reports bloom into early autumn. Bees and other insects visit the flowers. Brown, bean-shaped pods hold several seeds and appear from July to September. Leaves feed caterpillars, including those of the silver-spotted skipper. Mammals eat the fruits and roots.

Grow this vine in sun or partial shade. More sun gives stronger growth and more flowers. It favours rich sandy or gravelly loam that stays moist. It also tolerates clay when the soil drains well. Missouri Botanical Garden lists USDA zones 4–9; RHS rates it H6. Give young shoots a frame or canes to climb. Seeds and divided tubers provide new plants. The vine spreads through seeds and tubers and can become weedy. It suits edible gardens, screens, and damp woodland edges. Major pest and disease problems are uncommon. Slugs and snails may cause damage, but pruning is not needed.

Indigenous peoples ate the tubers and taught settlers their use. Cooked tubers taste nutty and have a fine texture. They contain about three times the protein found in potatoes. Roast, boil, mash, or fry them as a food crop. Seeds and pods are edible too; PFAF also lists leaves. Wait two or three years for a larger tuber harvest. Autumn is the preferred harvest season. PFAF reports no known hazards, rather than confirmed safety for all uses.