Apocynum cannabinum

Did You Know?

• The plant is a larval host for the snowberry clearwing (Hemaris diffinis), a pollinator resembling a small hummingbird.
• It also hosts the dogbane tiger moth (Cycnia tenera) and the zebra caterpillar (Melanchra picta).
• The stems contain a white sap capable of causing skin blisters.

Description

This plant grows to about one meter tall, with reddish stems that ooze a milky sap. Its broad, lance-shaped leaves grow in opposite pairs, measuring 7 to 15 centimeters long and 3 to 5 centimeters wide; they are smooth on top and hairy underneath. Blooming from July to August, it bears a white, five-lobed flower. The lightweight seeds, covered in silky white hairs, can travel by wind or water. Its roots are short rhizomes and horizontal runners.

Taxonomy

Carl Linnaeus described and named Apocynum cannabinum in 1753. It belongs to the genus Apocynum within the family Apocynaceae. The genus name means 'poisonous to dogs,' and the specific epithet cannabinum, along with common names like hemp dogbane, references its similarity to Cannabis as a fiber source. It has no accepted subspecies but has synonyms.

Uses

The stems contain bast fibers that are fine, strong, and silky, used by Native Americans to make bows, fire-bows, nets, tie-down straps, hunting nets, fishing lines, bags, and clothing. According to Craig Bates of the Yosemite Museum, five stalks yield one foot of cordage, and a large root-storage bag could take one to three months to complete. Stems are harvested in fall after leaves drop and stalks turn reddish-brown; cutting promotes regrowth, and unused stems are traditionally burned to encourage taller, straighter growth in spring.

The seeds can be ground into a powder and eaten raw or cooked. The latex sap, when left to harden overnight, becomes a white gum sometimes mixed with clean clay and used as chewing gum. The plant can absorb lead from soil through its roots, a process called phytoremediation. In herbal medicine, it has been used to treat fever and slow the pulse, and various Native American tribes employed it for rheumatism, coughs, pox, whooping cough, asthma, internal parasites, diarrhea, and to increase lactation.

The root serves as a tonic, cardiotonic, diaphoretic, diuretic, emetic, and expectorant, harvested in autumn and dried. A weak tea from dried root has been used for cardiac diseases and as a vermifuge, and the milky sap is a folk remedy for genital warts. However, illness and deaths have resulted from its medicinal use.