Dogbane (Apocynum cannabinum)

Apocynum cannabinum is the scientific name for the species more commonly called Dogbane, Amy Root, Hemp Dogbane, Prairie Dogbane, Indian Hemp, Hemp Dogsbane, Rheumatism Root, Dogsbane, or Wild Cotton. Dogbane is a perennial herbaceous plant that grows throughout much of North America—in the southern half of Canada and throughout the United States. It is poisonous to humans, dogs, cats, and horses. All parts of the plant contain toxic cardiac glycosides that can cause potentially fatal cardiac arrhythmias if ingested. Some Lepidoptera (Butterflies/Moths) can withstand the toxins and feed on this plant.

Dogbane occupies a wide range of habitats including prairies, open woodlands, roadsides, disturbed sites, and riparian edges. The plant typically produces clusters of small, greenish-white to reddish flowers from late spring through summer, followed by the development of slender, paired seedpods that contain numerous silky-seeded fruits carried by the wind.

Despite its toxicity to mammals, Apocynum cannabinum plays an ecological role in supporting certain insect species. Yellow-faced Bees and Sweat Bees are drawn to the flowers when in bloom, playing an important role in their pollination. Some Lepidoptera—specific butterflies and moths whose larvae have evolved physiological tolerances to the plant’s chemical defenses—are able to feed on its foliage and use it as a host plant such as larvae of the Snowberry Clearwing (Hemaris diffinis), and Dogbane Tiger Moth (Cycnia tenera), of which there is evidence that the adult Dogbane Tiger Moth emits aposematic ultrasound signals; these may also jam bat echolocation, causing bats to miss their target, but even if caught, release them due to the concentration of compounds derived from Dogbane. Adult Feeders of Dogbane are Great Ash Sphinx (Sphinx chersis), Apple Sphinx (Sphinx gordius), Poecila Sphinx (Sphinx poecila)

The Milkweed Tussock Moth (Euchaetes egle) may be able to be moved to Dogbane if they are applying heavy pressure to locally limited supplies of Milkweed which belongs to the same family as Dogbane (Apocynaceae) however, we recommend allowing the Milkweed Tussock Moth larvae to finish their cycle on the Milkweed they were deposited on, as the plant will not be killed by even being fully skeletonized. in fact, there is evidence that heavy pressure by Tussock moth larvae stimulates new growth of fresh and tender leaves that are then an advantage to late forming Monarch larvae who host on the Milkweed species.

In this way, Dogbane contributes to local biodiversity by providing food resources for specialist herbivores and, indirectly, for predators and parasitoids that depend on those herbivores. Gardeners and land managers considering the species for native planting should weigh its ecological benefits against its risks to people and animals and should take precautions to prevent accidental ingestion while recognizing its deep value within native plant and pollinator communities.