Corylus heterophylla aka Siberian Filbert

Corylus heterophylla is a deciduous shrub in the birch family, Betulaceae. Its common names include Siberian hazelnut and Asian hazel. Its native range spans southeastern Siberia, China, Mongolia, Korea and Japan. It grows in temperate woods and along woodland edges. It also forms dense thickets on mountain slopes. The plant usually grows as a shrub, though some become small trees. It can reach 23 feet [7 metres] tall.

The bark is grey, and the leaves vary in shape. Some leaves are long and narrow; others are broad or nearly round. Their thin blades have uneven, double-toothed edges, often with lobes. The upper face lacks hairs, while hairs follow veins beneath. Slender stalks hold the leaves on the stems. This mix of leaf shapes helps explain the species name.

Yellow male catkins hang in groups of two to five. Small groups of female flowers grow on the same plant. Wind carries the pollen, and PFAF lists the species as self-fertile. Flowers appear from April to May. The rounded to egg-shaped nuts ripen from September to October. Their shells enclose seeds rich in oil. Oregon State describes the husks as fairly open. People gather wild nuts and sell them in local markets.

Grow this hazel in sun or partial shade with moist soil. It accepts sandy, loamy and clay soils, but loam suits it well. Moderate soil fertility gives better seed yields than rich or poor ground. It tolerates alkaline soil but dislikes very acid ground. Strong winds pose less trouble than exposure to sea winds. PFAF lists USDA zones 4–8; Oregon State also confirms zone 4 hardiness. Woodland edges and gardens with light shade offer suitable sites. Coppicing is another supported way to manage the plant.

The seeds can be eaten raw or cooked, or pressed for edible oil. Unshelled nuts can keep for at least a year in cool storage. Squirrels may take the crop before harvest. Growers in Asia cultivate this species for nuts. PFAF reports poor value as a nut crop in Britain. It also records seed use to aid appetite and digestion. This is a reported use, not proof of medical benefit. PFAF lists no known hazards, but this does not establish safety for every use.