Wild grapes

Many of native wild grapes are now bearing fruit, but you'll have to hurry to spot them because they are being devoured by wildlife. Porcelain berry has become an invasive plant.

There are a number of species of wild grape, with fox, summer and riverbank grapes probably being the most abundant in Frederick County. Wild grape has leaves with three lobes, a small, greenish-white flower that blooms between May and June and a dark, purplish fruit that develops in late August or September.

Courtesy Photo

Grapes form on vines that can attach to trees by tendrils and develop as the host plant grows. The grapevine develops a shaggy, woody appearance and can become quite large in diameter. Grapevine can damage the host plant by covering its leaves, strangling it or adding weight, which can make it more likely to experience storm damage during high winds or ice storms.

Despite this damage, grapes are one of the most abundant producers of fleshy, soft mast for animals and one of the most universal food sources for wildlife, especially birds. Grapes that escape initial consumption often dry up and become raisins that animals can consume throughout fall and winter when food is scarce.

The woody vine and leaves can become quite dense, which provides cover for wildlife, especially species like grouse, brown thrashers and cardinals that prefer thick cover. The woody strands that peel off the vine also make ideal nest material for many birds.

Early European colonists did not fancy the sour wild grapes for wine production and imported European varieties for this purpose. There are a growing number of winemakers that prefer the tart, fuller flavor that wild grapes impart to wine. Most winemaking guides suggest discarding the seeds and skins and add sugar to native grapes to ensure that the drink is not too sour or acid.

Grapes, especially red and purple varieties, have beneficial antioxidants, such as resveratrol, that have been shown to inhibit some cancers, promote heart health, enhance the skin and help control Alzheimer's disease among other benefits.

Porcelain berry

There is an introduced member of the grape family known as the porcelain berry

(Ampelopsis brevipedunculata) that has become an invasive pest covering many woody landscapes, especially along streams and other wetland areas.

Porcelain berry was brought to this country during the late 1800s for use in landscapes. This hardy, fast-growing exotic soon escaped captivity and is now growing throughout the East. Porcelain berry can quickly overtake native landscapes and smother small trees and shrubs.

It is similar to wild grape except the porcelain berry has a white-colored inner bark (pith) while native grapes have a brown-colored pith. The porcelain berry also has brown-and-white-colored dots (lenticels) along its vine while the native grape does not. Native grapevine has a peeling, shaggy bark whereas the porcelain berry's bark is smooth.

The actual berry has a shiny "porcelain" look to it and they can be multicolored, whereas the grape is duller and more uniform in color.

Nature Notes for 9/4/2011