Snailseed Vine is often mistaken in its native range for the vicious thorned Greenbriar Vine or the ubiquitous Moonseed Vine.
However Snailseed Vine (Cocculus carolinus) is a delicate and beautiful vine, much better behaved than many gardeners would lead you to believe. It makes an excellent shade or sun, twining vine. The bright green, glossy, heart-shaped leaves climb trellisses or wire fences quickly in the spring.
In fall it bears grape-like clusters of bright pea-size red berries that draw songbirds. The Christmas red berries against Christmas green leaves create a dramatic and striking display through fall until a hard freeze.
A freeze will take the leaves off the delicate vine, and soon after the birds will remove the red berries. As long as the roots don’t freeze, it will come back next spring. However, it is not perennial in the north where a deep soil freeze will kill its roots.
In spring and summer, Snailseed is often mistaken for Greenbriar (Smilax sp.). Yet they are so easy to tell apart by touch. Greenbriar has vicious thorns even when young, and the strong woody stems and climbing tendrils are tough and hard to break. Snailseed stems are smooth and delicate, break easily with a light tug. No thorns, no tendrils. It climbs by twining its stem around a support. Both have smooth, heart-shaped leaves, but briar is thick, almost succulent, and Snailseed is thin and easily bent or torn, and is covered with short soft hairs.
Snailseed is also often confused with a close relative by name but not by temperament. Moonseed (Menispermum canadense) has a similar leaf and twining habit, but has blue berries. Moonseed spreads aggressively by rhizomes, is difficult to remove, and ranges over the entire eastern U.S. and Canada from the Gulf Coast to Hudson Bay. This much tougher plant is easy to tell apart from Snailseed in the fall by berry color. While they have similar seeds, the Snailseed seed is a fully round coil, thus its nickname of “Carolina Moonseed” referring to the full moon. The tougher Moonseed seed has a bite taken out of the edge, making it look like the crescent moon. So if your seed is full, that’s the good Snailseed, but if it’s crescent, that’s the aggressive Moonseed.
Because Snailseed can creep along the ground looking for a support to twine up, it is also mistaken for several ivies. Its heart-shaped leaves sometimes have side indentations that are best described as “elephant head shaped”. But since Snailseed is a twining vine, it lacks the grasping tendrils or the damaging aerial rootlets of ivies and more aggressive vines. Check the nodes, where the leaf meets the stem – if it has tendrils or rootlets, it is not Snailseed.
Snailseed grows easily throughout Texas and in USDA Zones 5-9. Propagation of the pretty and delicate vine is easily done from seed. Gather the clusters of pea-size bright red berries in the late fall and clean off the fully ripe fruit. The quarter-inch coiled snail inside is the seed. Plant in fall or store the bare seed in the refrigerator through the winter for three months of cold stratification to plant in early spring. Plant shallowly in part shade to full sun at the base of a trellis or wire fence so it will have structure to twine on.
It is not picky for soil or moisture. Snailseed is fast growing and will cover a fence or trellis quickly in spring, getting 5-6 feet wide and climbing 10-12 feet on structures. Prune to keep it confined; it spreads easily, but dies back considerably in the fall. Near the Gulf Coast, Snailseed can be semi-evergreen; in north Texas it is deciduous and drops its leaves after the first freeze.
Leave the bright red berries to feed the winter birds – they are toxic to humans.