Flower:

Clusters of ¼-inch or smaller tubular or bell-shaped flowers. Individual flowers have 5 white, greenish or yellowish petals, fused at the base, the lobes erect or flaring. One plant usually has several clusters, at the top of the plant and at the end of branching stems in the upper part of the plant. The center, terminal flowers in the cluster open first. The clusters start out round then spread out to a broader, more flattened cluster.

Leaves and stem:

Leaves are generally oval with a sharply pointed tip, rounded or heart-shaped at the base, 2 to 6 inches long and to 2½ inches wide with smooth edges and white or cream colored veins. Leaves are mostly stalkless or with a minute stalk (especially on upper leaves), usually clasping the stem with the rounded leaf bases overlapping on the leaf pairs. The underside of the leaves is sometimes slightly hairy. Stems are typically hairless and reddish brown and exude a milky sap when broken The leaves and stem can have a waxy feel to them.

Fruit:

Fruit is a pair of hanging, slender, slightly curved pods 4 to 8 inches long. Inside are small brown seeds with a tuft of white hair to carry them off in the wind.

Notes:

Clasping Dogbane and the related Indian Hemp (Apocynum cannabinum) are very similar, the only noticeable difference is the latter typically has longer stalked leaves (but not always!). Clasping Dogbane may also grow up to 4 feet tall but is often 2 to 3 feet. In some references, Apocynum sibiricum is considered the same species as Apocynum cannabinum, but Flora of North America, our definitive reference, treats them as separate species.