Spreading dogbane (Apocynum androsaemifolium) is a native perennial found growing to heights of 1/2 to 2 feet in well-drained sites throughout most of North America, Canada and Northeastern Mexico.
The branched stems of spreading dogbane grow from rhizomes. When broken, the stems exude a milky sap. The opposite, oval leaves have a short petiole (stem) and droop slightly. The upper side of the leaf is green and the underside is a paler green. In the fall the leaves turn a bright yellow before falling.
Five petals unite to form a bell-shaped pink to white flower with flaring lobes and pink veins. The inflorescence, at the terminal end of spreading dogbane stems, is a cyme (branching with the upper flowers maturing before the flowers on lower branches).
Spreading dogbane fruits are thin, cylindrical pods containing numerous seeds. Each seed has a long tuft of cottony hairs.
Native Americans used employed spreading dogbane for a wide variety of complaints involving the heart, uterus, respiratory and urinary systems. Modern herbalists continue to use spreading dogbane. However, the plant contains glycosides, which can be lethal to both humans and livestock. Cymarin, a cardiac stimulant, occurs in the roots. Thus great care must be taken if spreading dogbane is used medicinally. Because spreading dogbane is toxic to livestock, it is categorized as a noxious weed when growing in dense stands on range land.
Spreading dogbane stem fibers are strong and were used for making thread or cordage. The spreading dogbane fibers are short, so if other fibers were available they were used preferentially over spreading dogbane fibers. The thread made from spreading dogbane stem fibers is reported to be stronger than cotton thread.
These spreading dogbane plants were growing on a trail to Crystal Lake (Lassen County CA).