Smilax tamnoides aka Bristly Greenbrier

Smilax tamnoides, or bristly greenbrier, is a woody, perennial vine. It belongs to the Smilacaceae family and loses its leaves each year. Its native range runs from southern Ontario into the central and eastern United States. It also reaches northeastern Mexico. It grows in woods, thickets, floodplains, and along streams. Tendrils let it climb shrubs and low tree branches. It can also trail across the ground.

Garden plants can reach 40 feet [12.19 metres] tall. Their spread can reach 6 feet [1.83 metres]. The vine grows fast and forms dense growth. Its round, green stems bear prickles and stiff bristles. Lower stems carry more spines than upper stems. These darken with age, becoming brown or nearly black. Old stems can turn brown too. The leaves grow in an alternate pattern along the stems. They are broad, hairless, and green, with paler undersides. Each leaf has three to seven veins. Leaf bases range from rounded to heart-shaped. Pairs of tendrils grow near the leaf stalks.

Small, star-shaped flowers form umbels in spring and summer. Their shades include yellow, white, green, and grey. Male and female flowers grow on separate plants. Both sexes must be present for seed production. Bees and flies pollinate the flowers. Dark blue to black berries follow, each holding one to three seeds. Birds eat the berries in fall and winter. Bears, raccoons, and other mammals eat them too. Moth caterpillars feed on the leaves. Deer may browse the stems and foliage.

The plant grows in sun, partial shade, or dappled light. Moist loam suits it best, though it accepts many soils. It tolerates wet ground and some drought. It grows across acidic, neutral, and alkaline soils. North Carolina State lists USDA zones 4–8. The vine fits woodland plantings, native gardens, and rain gardens. Dense growth can form a barrier or hedgerow. Trailing stems can help hold soil on banks and slopes. Its bristly stems make handling and control hard. Sources disagree about how much it spreads from seed. North Carolina State also reports spread through rhizomes. The plant has a high fire risk.

Young leaves, shoots, and tendrils are edible in salads. Cooked roots provide starch and can be dried into flour. Recorded folk uses include teas, poultices, and root washes. These records do not establish medical benefits. Plants For A Future reports no known hazards. North Carolina State identifies it as non-toxic to cats, dogs, and horses. Prickles remain a physical hazard when handling the vine.