See list of Smilax species

Smilax is a genus of about 200 species of perennial woody and thorny vining flowering plants in the monocotyledon family Smilacaceae, native throughout the tropical and warm temperate regions of the world. Common names include Catbrier, Greenbrier, Prickly-ivy, Sarsaparilla, Sarsparilla and Smilax. The herbaceous plants formerly included in this genus are now placed in Nemexia. For a full species list, see list of Smilax species; selected common species include:
Smilax aspera (Common Smilax)
Smilax bona-nox (Saw Greenbrier)
Smilax glauca (Cat Greenbrier)
Smilax hispida (Bristly Greenbrier)
Smilax regelii (Sarsaparilla)
Smilax rotundifolia (Common Greenbrier)

On their own, Smilax plants will grow as a shrub, forming dense impenetrable thickets. It will also grow over trees and other plants up to 10 m high using its hooked thorns to hang on to and scramble over branches. The genus includes both deciduous and evergreen species. The leaves are heart shaped and vary from 4-30 cm long in different species.

Greenbrier is dioecious, however only about one in three colonies have plants of both sexes. Plants flower in May and June with white/green clustered flowers. If pollination occurs, the plant will produce a bright red to blue-black spherical berry fruit about 5-10 mm in diameter that matures in the fall.

The berry is rubbery in texture and has a large, spherical seed in the center. The fruit stays intact through winter, when birds and other animals eat them to survive. The seeds are passed unharmed in the animal's droppings. Since many Smilax colonies are single clones that have spread by rhizomes, both sexes may not be present at a site, in which case no fruit is formed.

Ecology

Smilax is a very damage-tolerant plant capable of growing back from its rhizomes after being cut down or burned down by fire. This, coupled with the fact that birds and other small animals spread the seeds over large areas, makes the plants very hard to get rid of. It grows best in moist woodlands with a soil pH between 5 and 6. The seeds have the highest percent chance of germinating after being exposed to a freeze.

Besides providing an important fruit for animals (especially birds) during the winter, the greenbrier plant also provides shelter for many other animals. The thorny thickets can effectively protect small animals from other larger animals who cannot enter the greenbrier. Deer will eat the foliage.

Uses

An extract from the roots is used to make the drink Sarsaparilla. The roots may also be used in soups or stews, the young shoots can be eaten raw or cooked and are said to taste like asparagus, and the berries can be eaten both raw and cooked.