Latin Name: Apocynum androsaemifolium
Common Name(s): Spreading Dogbane
Family: Apocynaceae
Size: up to 2 feet tall. Can establish large colonies by spreading rhizomes.
Life Cycle: Perennial
Distribution: Most of North America in sunny environments. Seems particularly fond of roadsides and ditches.
Light Requirements: Full sun.
USDA Zone: 3a to 9b
Drought Tolerance: Quite high once established.
Fire Risk: Presumably low while it is growing, given the soft watery leaves. If growing near a structure in a fire-prone area it is probably best to cut it down after it dies back and dries to avoid the seed fluff and dried plant matter fueling any fires.
Cultivation Notes
Dogbanes are tough and adapt well to the garden. They need full sun and can adapt to a variety of soil conditions, but spreading dogbane in particular generally do not appreciate wet soil for long periods of time and wants decent drainage. Once established the plants should do fine without summer irrigation, but make sure they receive regular water when young. Fertilization not needed, as the plants do fine even in poor and gravelly soil. Slug control may be needed when the plants are young, as heavy feeding by non-native slugs can kill young plants. Simply remove slugs in the evening and kill in soapy water.
Ecology
The interesting flowers bloom from June through August and are very attractive to pollinators. The seeds are consumed by birds in the winter, when few food sources are available.
Uses
Spreading dogbane is toxic, containing cardiac glycosides. They have been used for fiber and the latex can be turned into rubber, similar to common dogbane.
Propagation
Seed or by division. Seeds are easily collected and can be sown directly in the fall or in spring. Sow just under the soil surface. Germination can be slow and often is irregular. If planting in the late spring, cold stratification will likely be needed for up to two months before germination will take place. I have not had too much luck with seeds, though. I have successfully propagated the plants by letting seedlings develop naturally, then moving them. I have also taken divisions with some success. They do not seem to resent disturbance as much as milkweeds, their close relatives.