Apocynum cannabinum
hemp dogbane
Overview
Apocynum cannabinum is an erect, branching perennial in the dogbane family, growing 1-5 feet (30-150 cm) tall from spreading rhizomes. The smooth, often reddish stems and all other parts exude a milky white latex when broken. Opposite leaves are oblong to lance-shaped, 2-5 inches (5-13 cm) long, with smooth margins and a pale underside. Small greenish-white, urn-shaped flowers about 0.2 inch (4-6 mm) long are borne in branched terminal clusters through summer. These are followed by paired, slender, curved seed pods 4-8 inches (10-20 cm) long that split to release seeds tipped with silky white hairs. The plant spreads aggressively by deep rhizomes and seed, forming colonies in fields, roadsides, and stream banks, and is treated as a weed of cultivated ground across North America. All parts contain cardiac glycosides such as cymarin, which are poisonous to humans, livestock, and pets, and the latex can irritate skin. Tough bast fibers in the stems were used by Indigenous peoples to make cordage, nets, and textiles, giving rise to the names Indian hemp and hemp dogbane.
Native Range
Native throughout North America, from southern Canada across the United States into northern Mexico. It grows in open habitats including fields, prairies, ditches, and the banks of streams and ponds.Suggested Uses
Rarely cultivated; it is known mainly as a source of tough stem fiber historically used for cordage and netting. In restored prairies and field margins it serves as a summer nectar plant for pollinators. The dried seed pods are sometimes used in arrangements.How to Identify
Appearance
Size & Dimensions
Height1' - 5'
Width/Spread1' - 3'
Reaches mature size in approximately 2 years
Bloom Information
Blooms through summer, generally June to August, with greenish-white flowers in branched clusters at the stem tips. The flowers draw bees, wasps, and butterflies for nectar. Slender paired seed pods develop afterward and persist into autumn before splitting open.
Detailed Descriptions
Foliage Description
GreenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight