Smilax bona-nox


Illustration of catbrier leaves, flowers, fruits
Catbrier, Smilax bona-nox
Paul Nelson
Other Common Name
Greenbrier; Bullbrier; Tramp’s Trouble

Smilacaceae (greenbriers)


Catbrier is a stout, spiny, woody perennial vine with stems that are often 4-angled, either low-climbing or extensively climbing by tendrils to a height of 25 feet.

Leaves are alternate, simple, 1½–4½ inches long, ¾–4 inches wide; heart-shaped, broadly egg-shaped, triangular, or sometimes fiddle-shaped; margins much more thickened than the rest of the leaf (see the underside); margins can be entire or set with stiff prickles; upper surface green, smooth, sometimes with white blotches, veins thickened and conspicuous in a network over the leaf surface; lower surface sometimes paler, usually with a few thorns on the midvein. The leaves are often somewhat leathery and drop off in winter.

Stems are stout canes, strongly angled, and green, with at least the older stems more or less with tufts of small, star-shaped hairs; prickles stout, green to brown or black, to ¼ inch long; tendrils arising in pairs at the base of leaf stalks. The bark is green, hard, often roughened with white scales.

Flowering is in May–June. Flowers are yellowish green, small, with male and female flower clusters on the same plant, clusters with 3–20 flowers; petals 6. The cluster’s stalk is much longer than the leaf stalk at its base.

Fruits mature September–October. Fruits are round black berries, ¼ inch thick, occurring on stalks about 1 inch long in globe-shaped clusters. Seeds usually 1 per fruit.

Key Identifiers


  • Leaves are not whitened with waxy coating on the undersurface, though they might be slightly lighter colored than above.
  • Stalk of flower clusters are much longer than leaf stalk at its base.
  • Leaf margins are thickened, about as thick as outermost main veins.
  • Leaf margins are entire or with sparse, irregular, white, spinelike projections.
  • Leaves with network of raised, thickened veins on undersurface.
  • Leaves are sometimes fiddle-shaped.
  • Stems are often 4-angled.

Stems can be more than 26 feet long.

Habitat and conservation

Occurs in dry to mesic forests, edges of glades and bluffs, fencerows, old fields, and frequently in thickets.

Distribution in Missouri

Scattered in the southern half of the state.


The greenbrier family is one of the few groups of monocot plants that can have woody stems. (Other monocots include grasses, orchids, lilies, and cattails.) There are 8 species of Smilax in Missouri; 4 are woody, perennial, and bear prickles (the stems are stout and are not easily crushed), and 4 are herbaceous, annual, and lack prickles (you can easily crush the stems, even when dry). If you have a hard time distinguishing between the different Smilax species, don’t feel bad; professional botanists often have trouble, too, especially if specimens are incomplete.

Human connections

In low-lying areas, catbrier can form impenetrable thickets. Catbrier rootstocks have been used to prepare a root beer–like beverage. The tender young shoots of many greenbrier species can be eaten like asparagus or fresh greens. Native Americans used the plant in a variety of ways.

Ecosystem connections

At least 13 species of birds eat catbrier fruits, including several songbirds, wild turkey, wood duck, and ruffed grouse. Several mammals eat the fruits, too. Deer browse these plants. A sprawling mass of stickery catbrier stems offers good cover for small mammals and birds.