One of the most common plants you come across at the edge of mesic deciduous forests, disturbed sites and dry uplands where fire is rare or has been suppressed for several years is one of Florida’s most hated. While listed as an invasive yet widely (and legally) planted for its ornamental value in Great Britain, virginia creeper (Parthenocissus quinquefolia) is native to most of the United States yet often considered a weed because of its vigorous growth and somewhat aggressive behavior, similar to English ivy (Hedera helix.) However, these traits, together with its bright red fall color and its interesting foliage, can make this plant very useful in the landscape on a large trellis or to hide unsightly structures with smooth surfaces as it climbs via adhesive pads.
Virginia creeper’s genus name Parthenocissus, meaning “virgin ivy,” and its specific epithet quinquefolia, which translates into “five-lobed leaf,” speaks to its being commonly confused with poison ivy (Toxicodendron radicans), which can be distinguished by its shiny three-lobed leaves. Another feature that often leads to confusion is its dark purple to black berries that resemble wild grapes (Vitis spp.) While the latter are edible, the berries (and leaves) of virginia creeper are said to be toxic due to their oxalic acid content, which can cause kidney damage and nausea if eaten in large quantities, as well as for their microscopic calcium oxalate crystals (called raphides, see photo under 400X magnification), which can cause numbing, followed by mildly painful edema.
Why the berries contain these defense mechanisms is unknown but they are believed to prevent consumption by animals that are less effective at dispersing their seeds, leaving more food for the plant’s primary vectors. Nevertheless, the berries are eaten by a number of animals, including squirrels, deer, skunks, raccoons, and especially songbirds that often nest in the plant’s thickets, the latter explaining the wide range of this plant. Seed dispersal by many different species of animals makes virginia creeper less susceptible to environmental changes, in contrast to plants like nightshades (plants in the family Solanaceae) which are eaten and dispersed only by birds and are otherwise more immediately toxic to most mammals. Its generalization is not restricted to the manner of its dispersal as its inconspicuous green flowers are pollinated by a wide range of bees such as leafcutter bees (Megachilidae), the European honey bee (Apis mellifera), sweat bees, and wasps, making it a highly valuable element for wildlife in many different woodland ecosystems between spring and fall.
Landscape managers must necessarily make decisions based on a plant’s interactions with its environment. If the plant is native to the community in which it occurs, it fulfills a role in that community that is often necessary to its integrity. This must be recognized while ignoring any potential cultural bias, aesthetic, or personal preferences. Whether a species is a pest here is determined by its nativity and historic role in certain plant communities that are kept in ecological balance (or equilibrium) by complex dynamics and natural disturbances like fire. However, our cultural relationship to plants is epitomized by woody vines like wild grapes or virginia creeper. The latter is considered an ecological pest in Great Britain but due to the rather positive cultural relationship of the British to vines like English ivy, it is often considered highly ornamental on houses or walls. The opposite is the case in the United States where vines are often associated with abandoned lots and untamed nature. Culture and nature cannot be further apart here. There is still a long way to go.