By Jeanne Henderson
Two species of native wild grapes occur in the Great Lakes Bay Region. The wide-lobed leaves of summer grapes and riverbank grapes grow on a vine with tendrils. The tendrils are modified flower stalks, growing opposite of almost every leaf, reaching outward until they touch something. Tendrils twist or curl as they attach to another plant, post or trellis for support. After studying the movements of climbing plants in 1865, naturalist and biologist Charles Darwin, coined the term “circumnutation” to describe the circling movements.
Grapevines host many natural food chains and webs. Look closely during the summer to find caterpillars of sphinx or geometer moths. At least five beetle species chew on the leaves, while some close the leaves over themselves for shelter. Songbirds that consume grapes include pileated and red-bellied woodpeckers, robins, catbirds and cedar waxwings. Game birds such as ruffed grouse, wild turkey and ring-necked pheasants relish the fruits too, as do mammals like raccoons, squirrels, opossums and black bears. These all reveal their grape-loving binges by the seeds deposited in their scats or droppings. After leaves fall off, you may find spherical nests in the tangled vines from red squirrels or white-footed mice. Certain birds like the Baltimore oriole pick off strips of grapevine bark to weave into its hanging nest. Other birds using this building material include red-eyed vireo, brown thrasher and northern cardinal.
When growing in favorable conditions, grapes are opportunistic high climbers that make their way to treetops. When they cover living vegetation, they block sunlight, which damages or kills their host. November is a good time to assess vines and decide whether pruning is needed to retain the health of your trees and shrub
Fruit to the Vine
Riverbank grapes (vitis riparia) are very common and grow in floodplains, along riverbanks and near lakes and railroads right-of-ways. Their vines may reach a diameter of 4 inches as they hang down from treetops as if waiting for Tarzan to swing on them. Leaves grow 2.5 to 8 inches long and nearly as wide. Early leaves have shallow lobes with coarsely toothed edges. Later leaves are distinctly three-to five-lobed with U-shaped sinuses between (similar to maple leaves) and are a lustrous bright green. Their purple berries are juicy and tart when ripe, then sweeten after frost.
Summer grape (vitis aestivalis) leaves are of similar shape and size. The upper leaf surface is bright green while covering the lower surface with tiny white hairs. In both species, the tendrils are absent from every third leaf node. Summer grapes like growing in drier upland sites such as oak-hickory forests or wooded dunes. Their bluish-black berries are edible but sour.
Making grapevine wreaths is one way to reuse the flexible stems after you’re done pruning. Add dried or silk flowers, grasses and a bow for finishing touches. Hang the decoration on a door or wall. Remember the vine as it grew its abundant leaves and the many species of wildlife who lived on it, knowing that this renewable resource will grow back next year.