Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Spreading dogbane

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Leaves
7. Flowers and Fruit
8. Habitat
9. Similar Species
10. For more information...

Name: Spreading dogbane, Apocynum androsaemifolium L.,

Other Names: apocyn à feuilles d'androseme, Indian hemp, fausse herbe à la puce

Family: Dogbane Family (Apocynaceae)

General Description: Perennial, reproducing by seed and by spreading underground rhizomes.

Photos and Pictures

Spreading dogbane (left - top of a flowering plant; right - maturing plant showing pencil-shaped seedpods).

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

Stems & Roots: Stems erect or leaning, occasionally unbranched but usually repeatedly branched in the upper part, 20-75cm (8-30in.) 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 & 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 (¼-2/5in.) long; seedpods usually in pairs, 7-20cm (3-10in.) 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.

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.

Similar Species: 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.

For more information...

... on weed identification, order OMAFRA Publication 505: Ontario Weeds

... on weed control, order OMAFRA Publication 75: Guide To Weed Control

...on weeds in field crops, contact Mike Cowbrough (mike.cowbrough@ontario.ca), Weed Management Specialist (Field Crops), OMAFRA, Guelph
...on weeds in horticultural crops, contact Kristen Callow (kristen.callow@ontario.ca), Weed Management Specialist (Hort Crops), OMAFRA. Harrow

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