September 15, 2021
As summer transitions into fall, the grapevines begin to ripen in the Hudson Valley. New York has a few different native species of grape (Vitis spp.), with river grape (Vitis riparia) and fox grape (Vitis labrusca) being the most common in the wild. Native grape species are commonly observed and can grow in a wide range of habitats, including clearings, forests, thickets, disturbed areas, and along streambanks. Grapevines provide a valuable food source for a wide variety of bird and mammal species. Many people are familiar with what grapevine looks like: a woody vine with dark brown peeling bark, wide leaves, and greenish fruits that ripen into a deep purple color.
Have you come across a grapevine with bizarre colored fruits before? Likely you were actually observing porcelain-berry (Ampelopsis brevipedunculata), a non-native lookalike that is easily mistaken for grapevine. In fact, porcelain-berry is also a member of the grape family (Vitaceae) but is native to Asia. It was introduced in the mid-to-late 1800s as an ornamental plant and has become established from Long Island throughout the Hudson Valley. The leaves of porcelain-berry are highly variable: some are deeply lobed with sinuous margins, while others are wide and serrate, much like a grape leaf. Porcelain-berry is often found in floodplains, thickets, and early successional woods and can grow in dense mats that can shade out native vegetation which makes it a problematic invader. Native grape species can also grow this way, so while native, some people still consider grapevines as invasive. Often, we think of the terms “invasive” and “non-native” as synonymous, however that is not always the case.
So, how can you tell the difference between native grapes and non-native porcelain-berry? The easiest way is to look at the fruits once fruiting begins in September. The fruits of porcelain-berry are speckled, and all shades of blues, pinks, purples, greens, and white, with one vine usually displaying several different colors. Native grapes are green or purple and are not speckled. When identification with fruits is not possible, cut open a twig and look at the color of the pith (the central region inside of a twig). Native grapevines have brown piths while porcelain-berry has a white pith.
Infestations of porcelain-berry can be treated by cutting the vines and applying herbicides. Be sure to manage porcelain-berry before summer fruiting, to prevent new seeds from becoming established in the seed bank. If you see porcelain-berry, you can report it to NY iMap Invasives to help control the spread. Click here to learn about other invasive species and their native look-alikes.
Variability in leaf shape of porcelain-berry. Photo Credit: Ruth Ann Grissom, The University of North Carolina at Charlotte https://www.plancharlotte.org/story/invasive-vine-porcelain-berry-eats-trees-charlotte-nc-park
Native grapes: Photo Credit: Paul Rothrock https://sernecportal.org/portal/taxa/index.php?taxon=105338&clid=4063
Photo Credit: Joe Boggs, OSU Extension https://bygl.osu.edu/node/1129