Some species prefer rich and moist soils while others thrive in dry and sandy soils. Grape is an important source of food for a variety of songbirds, gamebirds, and small mammals. While grapes are beneficial to wildlife, the vines can also cause problems. Grape vines grow into the tops of trees by growing up with the tree from the seedling stage or by growing into the canopy from a neighboring tree. The trees can become disfigured or killed when the vines become weighed down by snow and ice, in the winter. The vines can also block light from reaching the tree's leaves. This slows the tree's synthesis of food causing the tree to grow at a slower rate.
Grape grows as high-climbing or trailing woody vines with shreddy bark. The height of the vine can reach up to 15 meters because the vine often grows up with the trees and spreads across the canopy. The simple, alternate leaves are toothed, heart shaped, and often lobed. The leaves vary in length from two to nine inches. The dark, thornless stems can be hairy and have tendrils, which are used for support. Many species of grape are dioecious, having separate male and female plants. The vines produce green flowers between May and July. The spherical, purple to black fruit appear between July and October and can remain on the vine through the winter. Grape fruits range from 1/8th to one inch in diameter, hang in clusters, and are edible. However, but their taste varies greatly between tart and sweet.
Wild grape seeds require full sunlight to germinate. The seeds are spread by the birds and small mammals that feed on the fruit. Once buried in the soil, a grape seed can lay dormant, for many years, waiting for the required conditions to sprout. Grape can also sprout from the roots or the cut vine stumps. These characteristics allow grape to become established after a heavy timber harvest.
There are three chemical herbicides available to control grape. Dicamba can be applied as a foliar spray, basal bark, or spot application. Fosamine herbicide works as a foliar spray. 2,4-D herbicide can be used as a selective treatment when applied as a stump treatment, basal bark spray, or tree injection. Caution must be taken when using any of these herbicides, because they will kill non-target broad-leaf under-story plants, seedlings, and saplings.
The preferred method of grape control is by mechanical means. Severing the vines one to two feet about the ground works as a very effective control methods as long as the vines are growing under a forest canopy. After cutting, the vine will likely resprout. However, the sprouts and entire plant will die within three years, if in heavy shade. This method works because grape is shade intolerant. If this methods is tried in a young stand when the trees are under 18 feet tall and the forest floor receives a large amount of sunlight, the grape sprouts may be able to grow back into the tree crowns.
Prepared by Anne T. Lenox, Forest Resources Extension staff and undergraduate in Forest Science
The photograph is used with permission from OSU Extension, Ohio State University.