One of the most beautiful fall plants, now turning fences, trees, and fields crimson and blood-red here in the upper Midwest, is the vine Virginia Creeper. Except when it is really Thicket Creeper.
I’ve always known the common, five-leaved native vine as Virginia Creeper, Parthenocissus quinquefolia. It wasn’t until I began compiling a key to fruits important to birds that I realized much of what I thought was Virginia Creeper was really Thicket Creeper, Parthenocissus inserta (formerly P. vitacea). The two are superficially identical. A closer examination reveals that Virgina Creeper has adhesive pads on its climbing tendrils that enable it to “stick” to tree trunks and other surfaces. Thicket Creeper only has twining tendrils, so if it climbs, it does so on shrubs, chain link fences, or other substrate that allows it to “pull itself up.”
Virginia Creeper has duller leaves due to the fine, dense hairs that cover both upper and lower leaf surfaces. Thicket Creeper is shinier and mostly hairless. The flower and fruit structure is also different, with Thicket Creeper branching in twos, and Virginia Creeper having a more central axis to the inflorescence, if it flowers and fruits at all. Thicket Creeper produces fruits and flowers much more often than Virginia Creeper. In our wooded areas around campus, we find both species, but have only found fruit on Thicket Creeper.
The creepers are closely related to grapes (Vitis), often grow together with them, and have similar purple fruit which are loved by birds. Non-native, ornamental vines in the same family include Boston Ivy (P. tricuspidata) and Porcelainvine (Ampelopsis brevipedunculata). Although birds will eat those fruit, I don’t recommend planting the two latter species. They easily escape cultivation and can be invasive. On a personal note, their seeds are all so similar it makes it difficult for researchers like myself exploring migratory bird diets to figure out which fruits the birds are really eating!
For the most part, Parthenocissus in most of North America has simply been called Virginia Creeper. Many people are not aware of the morphological differences, and some authorities consider P. quinquefolia and P. inserta the same species. They seem very distinct to me. Take a look at the creepers near you – what do you think?