Summer grape is a vigorous vine climbing to a height of 35 feet by means of tendrils, or sprawling over low bushes and trees.
Leaves are alternate, simple, 2–8 inches long and wide, heart-shaped or egg-shaped to round; margins of some irregularly toothed and unlobed, some leaves with margins shallowly to deeply 3- to 5-lobed, lobe sinuses (cleft between two lobes) narrow and rounded, base heart-shaped; upper surface yellowish green with a few hairs on the veins; lower surface whitish, with light rusty, cobwebby hairs.
Stems are reddish brown, finely ridged, woolly at first but soon smooth; small branches are round in cross-section, not angled; tendril emerges opposite the leaf. Bark on branches shreds early; bark on older stems brown with long, papery shreds. Wood is tough, porous, pale brown, with a large pith.
Flowering is in May–June. Flowers are green, minute; male and female flowers in separate clusters on same plant; petals 5, dropping early. Clusters are ½–3 inches long; cluster stalk 2–6 inches long.
Fruit matures in July–October. Fruit dark blue to black globe-shaped berries, ¼–½ inch thick, with a thin whitish coating, sweet, juicy, in clusters 3–5 inches long. Seeds 2–4 per fruit.