Grapes are grouped together botanically into the genus Vitis, which comprises 65 species native to woodlands and thickets across temperate zones of the Northern Hemisphere. They are woody, deciduous vines or climbing shrubs, but often attached themselves to trees.
The stems of grape vines/shrubs develop a flaking bark and clamber over other plants to reach light. Young vines bear tendrils, which are modified stems that wrap around objects for clasping support.
Grape vines growing in the wild may grow up the trunk of tall trees and sprawl their foliage and fruits like a canopy over branches of the tree. Older grape vines may have a stem so large at its base that it may look like a narrow tree trunk.
Vigorous and healthy grape vines can slowly cause the death of a tree. The many stems and leaves block sunlight from the tree on which the grape clambers over. In time, the tree fails to make enough food from photosynthesis and it weakens and dies, leaving the grape there to use the tree's skeleton.