A few narrow-minded foresters might still refer to wild grapes as a detriment to the forest, but they actually are a great benefit. This perennial woody vine provides cover, food and nesting material for many Pennsylvania bird and mammal species and adds diversity to any forest.
Grapes, all originating as wild species, have been important to human civilizations for thousands of years. They grow all over the world. The Bible has many references to grapes and wine. Grapes are significant in the Jewish faith as one of the “Seven Species of Ketubah,” symbolizing eternal life, happiness and fertility of the land.
About 30 species and many more varieties of wild grapes (Vitis spp.) are found in North America. Those inhabiting the Keystone State include New England, summer, fox and frost grapes. In addition, grape species readily cross pollinate, creating unique hybrids.
Grapes send out tendrils from their stems, and these respond to touch by growing around and “grasping” any twig or branch with which they come in contact. This supports the vine as it climbs up trees. The vine’s brown bark is loose — often peeling off in thin strips. Bark strips from wild grapes are weaved by red squirrels to make their ball-like summer nests high in forest trees. Catbirds, cardinals, mockingbirds, brown thrashers and red-eyed vireos, as well as deer mice, also use grape bark as a major nesting material.
Grape leaves are toothed, have a basic heart shape and are often segmented into three lobes. While some are small, grape leaves grown in the shade can be up to 9 inches long. Dozens of insect species readily or specifically eat grape leaves. These include the grapevine looper, several sphinx moth caterpillars and Japanese beetles.
Grape flowers, often green, are fragrant but inconspicuous. Of course, it is their pollination and cross pollination that leads to all of the varieties that we have today.
Most attention is given to the fruit of wild grapes, and there is no doubt of its importance to wild animals and humans. Wild grapes occur in hanging clusters, are spherical and usually black or deep purple in coloration. Fruits vary greatly in size, taste and quantity. These variations occur between species, within species and from year to year.
It is a foolish hunter who doesn’t understand the importance of wild grapes to gamebirds. Grapes are a favorite late summer and fall food of ruffed grouse, wild turkeys and ring-necked pheasants. Grouse are often flushed from grapevine tangles where they were seeking shelter and food.
Many songbirds, including cedar waxwings, cardinals, robins, catbirds and a number of woodpeckers, consume the purple fruits. Grapes are also eaten by black bears, raccoons, skunks, opossums and fox squirrels. The main method of grape seed dispersal is believed to be through the solid wastes of these mammals.
Grapes are fermented commercially to make wine, but wild grapes also ferment on the vine. It is believed that animals sometimes get “drunk” from eating their fermented fruit. I once had a young wild turkey fly right towards me as I was working on the deck of my house. It crashed into a door and dropped dead. Its crop was filled with wild grapes.
We humans also enjoy eating wild grapes from the vine or making them into jelly, jam or wine. They are excellent sources of pectin and make thick jelly. The famous Concord grape was developed in Massachusetts in 1852 from our native fox grape (V. labrusca). All of Europe’s grapes grow on vines grafted onto North American roots.
One of the strengths of our native grapes is the genetic diversity they offer. This includes heat, disease and pest resistance. Jerry Eisterhold, a 72-year-old entrepreneur, was featured in the December 2023 issue of Smithsonian magazine for his efforts to propagate and experiment with 40 varieties of native grapes on his 14-acre Missouri farm.
This year has been a very successful fruiting year for grapes, and many clusters of purple fruits still hang in trees all across central Pennsylvania. Taste a wild grape and you will usually find it much tarter than the domesticated varieties, but important just the same. Wild grapes will be enjoyed by Pennsylvania wildlife all winter long.