Published February 5, 2022, in the McAllen Monitor.
Story and photos by Anita Westervelt, Texas Master Naturalist, South Texas Border Chapter
It’s February; it’s cold; the days are gray; the skies are gray. Who wouldn’t find a bit of joy spotting a pretty green vine to give hope to sunnier days ahead? If it’s the bright green of possum grape just beginning to peek out of a cold, brown landscape, it’s one of those native plants in the category, be careful what you wish for.
Possum grape (Cissus trifoliata) is also known as marine vine, marine ivy, sorrelvine, cow-itch vine and grape ivy. It is in the Vitaceae (Grape Family) but has no food value to humans nor wildlife – unless you’re a caterpillar. For me, that’s a saving grace: possum grape is a larval plant for the caterpillars of some of our more striking moths, like three types of the large sphinx moths, mournful, satellite and vine moths and host to Wilson’s Wood-nymph moth caterpillars.
As such, the fleshy leaves of possum grape are succulent-like, crisp, sturdy, attractive three-lobed and coarsely toothed; interestingly, especially at different growth stages, the leaf form can be quite variable, often confusing identification by novice plant aficionados. The leaves have a bad odor when snapped or crushed but certainly not a deterrent to munching caterpillars.
The plant’s tiny, insignificant, pale green spring blooms attract a large variety of insects to the nectar. The resulting ripe fruits are purplish black berries that grow in clusters like a bunch of grapes.
Generously, possum grape has been described as an attractive, ornamental vine that might make a pretty spill in a spills-thrills-fills multi-plant patio container. It’s touted as one of the easiest plants to grow in USDA hardiness zones 6 to 11, is fast growing, hardy, thornless, low-maintenance, resistant to deer, rabbits, drought, disease and insect infestation; and the leaves and seeds are consumed by bobwhite quail.
In reality, the fresh, new growth of tendril-climbing possum grape soon shows its true colors.
It climbs, attaching to objects and structures with miniature suction cups. Before you know it, it will have attached itself to fences or slinked up tree trunks, wending its way through the branches or coiled itself through chain-link fencing. On the ground, it sprawls; it will swath downed limbs, plants, large shrubs, and anything in its path. Left uncontrolled, it could take over small nations.
This hyper-active plant is native from Arizona to Georgia, and from Missouri through Mexico to northern South America. It is found throughout most of Texas, growing with total abandon anywhere in any habitat, in any condition, shade to full sun, from gardens to wastelands. Although easily pulled down, and out of tree canopies, the vines, woody at the base, are brittle and break easily, but it’s the underground works to worry about. The roots form huge tubers from which multi-directional new growth shoot out at random, and no telling the distance of that underground travel. The tuber must be dug up and removed to curtail the spread. The vine vegetation may cause contact dermatitis on skin; gloves recommended.
For all its wayward ways, possum grape is not on the Texas invasive plant list, but certainly it should be considered rambunctious.
