Dogbane, spreading, Apocynum androsaemifolium

Life Cycle

Perennial.

Propagation

Reproducing by seed and by spreading underground rhizomes.

Stems

Stems erect or leaning, occasionally unbranched but usually repeatedly branched in the upper part, 20-75cm high, slender, smooth, often reddish.

Leaves

Leaves opposite (2 per node), oblong to ovate, often drooping, on short stalks; upper surface bright to dark green, undersurface lighter green to whitish-green and finely hairy at least along the mid-vein, young leaves at ends of branches distinctly whitish.

Flowers and Fruit

Flowers in branched clusters at ends of stems and small branches; calyx lobes short and triangular; corolla whitish to pinkish, bell-shaped, 6-10mm long; seedpods usually in pairs, 7-20cm long, thin, pencil-like but more tapered towards the tip, straight or slightly curved, splitting lengthwise with a single slit to release the small, slender seeds, each with a long, white, silky parachute. All parts of the plant contain milky juice. Flowers from June to August.

Roots and Underground Structures

Spreading underground rhizomes.

Habitat

Spreading dogbane is a native plant that occurs throughout Ontario in pastures, edges of woodlands, waste areas, fields and roadsides, usually in dry areas or on shallow soils.

Distinguishing Features

It is distinguished by its slender somewhat fleshy appearance, its leaves opposite, short-stalked, often drooping, undersurface slightly hairy and lighter green, the younger ones whitish-green, its clusters of pinkish flowers usually 6mm (¼in.) or longer, its pencil-like seedpods, and milky juice.


Figure #1.

Spreading dogbane. A. Upper part of flowering plant. B. Cluster of seedpods.


Figure #2.

Note opposite leaves of dogbane.


Figure #3.


Figure #4.


Figure #5.

Hard, slender reddish stem of dogbane.


Figure #6.

Root of dogbane.