Mature follicles are 4-8" long, narrowly cylindrical in shape, and dark brown. These follicles eventually split open to release their seeds to the wind. Individual seeds are 4-6 mm. long, linear in shape, and brown; they have tufts of white hair at their apices that help to carry them aloft.

The plant exudes latex-like sap when broken or cut, which may irritate skin. It produces small whitish green flowers that become characteristic slender seed pods. The pods are reddish brown, sickle shaped, and 4 to 8 inches (10-20 cm.) long with slightly hairy, flat brown seeds inside.

The fruit of Spreading Dogbane consists of long, slender pods about two to 6 inches long, ripening from green to a dull red. Seed pods are produced in pairs. The pods release small seeds tipped by a tuft of cottony hairs. The latter help to disperse the seeds on the wind.

Fruit are a long, narrow pod up to 11cm (over 4 inches) long; each flower produces two seed pods. Inside the pods are many small seeds with fluffy tufts, much like milkweed or swallowwort seeds.