If you’re trying to identify this plant for the first time, you might reasonably assume it is a kind of milkweed. You’d be right. Dogbane is a milkweed relative—they are in the same Family— but in different genera (Apocynum vs Asclepias).
Young dogbane plants look very much like milkweed in terms of leaf shape and overall stature. As the plant ages, and once the flowers and seed pods appear, it becomes obvious that the two plants are quite different.
The leaves of dogbane are simple, entire, and elliptic in shape. The leaf tips are pointed and the base is round. The stem is hairless, and eventually turns a distinctive reddish-brown in color. The stem in older plants is much-branched.
The 5-petalled, white flowers are very small and nondescript. They occur in clusters at the tips of the branches. Fertilized flowers will produce stringbean-like seedpods, often in groups of two, that hang downward from the stem.
Like milkweed, dogbane exudes a white, sticky “milk” (or latex) when the stems and leaves are broken. The milk is toxic. Dogbanes and milkweeds contain cardiac glycosides that can interrupt the heart muscle’s normal functioning and cause cardiac arrest. Large mammals, including farm animals and dogs, can die if they consume enough of this plant matter. For this reason, the milkweeds and dogbanes are unwelcome colonizers in pastures and hay fields.
Dogbane is also known as Indian Hemp or Hemp Dogbane. American Indians used the stems of the plant to make rope, twine and baskets. Although the roots were once employed for a variety of medicinal uses too, all parts of the plant are extremely poisonous and should be avoided.
Look for Hemp Dogbane in open, sunny places, like fields, meadows, and roadsides.
Aside: There is a beautiful, and colorful beetle called the “dogbane leaf beetle” (Chrysochus auratus) associated with the dogbane plant. The beetle looks like a metallic rainbow of gold, green, blue, and red. Most of us have heard that bright colors are often “warning signs” in nature, and that’s the case with this iridescent dogbane beetle… Apparently, the insects feed on the plant and then store up the toxic compounds in specially-purposed glands. If the beetle is later disturbed by a predator, the foul toxins can be released externally to “deter” the predator. Ingenious!