Apocynum cannabinum grows up to 2 meters/6 feet tall. The stems are reddish and contain a milky latex capable of causing skin blisters. The leaves are opposite, simple broad lanceolate, 7–15 cm long and 3–5 cm broad, entire, and smooth on top with white hairs on the underside. It flowers from July to August, has large sepals, and a five-lobed white corolla. The flowers are hermaphrodite (have both male and female organs) and are pollinated by moths and butterflies.
It is a branched perennial that grows up to 1.5 m (5 feet) tall and has smooth opposite leaves and small greenish white flowers. Indians used the fibres from the stem to make bags, mats, nets, and cordage. Its milky juice, or latex, yields rubber, and the dried roots of Indian hemp and a related plant (A. androsoemifolium) make a drug that acts as a heart stimulant. True hemp (Cannabis sativa) is sometimes called Indian hemp.