Milkweed
Milkweed is the common name for flowering plants in the genus Asclepias, a group of herbaceous perennial plants in the dogbane family, Apocynaceae.
Milkweed is the common name for flowering plants in the genus Asclepias, a group of herbaceous perennial plants in the dogbane family, Apocynaceae. The genus includes roughly 140 species found mainly in North and South America, and many species are important host plants for monarch butterflies.
Description
Milkweeds are perennial herbs with opposite leaves, clustered flowers, and seed pods that release seeds with silky hairs. They are identified by their milky latex sap and complex flowers.
Distribution and habitat
The genus occurs throughout North and South America, with species found in diverse habitats such as roadsides, fields, woods, meadows, marshes, deserts, and prairies.
Ecology
Milkweed is ecologically important because monarch butterflies lay eggs on it and larvae feed on it. The plants also support many other pollinating insects with nectar and habitat.
Toxicity and uses
Milkweeds contain compounds that can be toxic to livestock and other animals. Some species have also been used ornamentally and in traditional food or medicinal practices, though handling and use vary by species.
Key facts
- Milkweed is a genus of flowering plants, not a single species.
- The plants are named for their milky sap, which oozes from damaged stems and leaves.
- Many milkweed species contain toxic cardenolides and other compounds that deter herbivores.
- Milkweed is the larval host plant for monarch butterflies, whose caterpillars feed on the leaves.
- Milkweed flowers provide nectar for many pollinators, including bees, butterflies, wasps, flies, and hummingbirds.
Milkweed is relevant in Canada because native species occur in Canadian habitats and are important for monarch butterfly conservation and pollinator gardens.
Frequently asked questions
What is milkweed?
Why is it called milkweed?
Why is milkweed important to monarch butterflies?
Is milkweed poisonous?
Where does milkweed grow?
Is milkweed used in gardens?
References
- Encyclopaedia Britannica — https://www.britannica.com/plant/milkweedSupports: Genus Asclepias, approximate number of species, family, and broad distribution.
- USDA Natural Resources Conservation Service — https://www.nrcs.usda.gov/sites/default/files/2022-09/Milkweed.pdfSupports: Milkweed habitat, toxicity to livestock, and plant characteristics.
- Selby Gardens EcoFlora — https://selby.org/ecoflora-milkweed-fun-facts/Supports: Milky latex as source of the name.
- University of Maine Extension — https://extension.umaine.edu/signs-of-the-seasons/indicator-species/milkweed-fact-sheet/Supports: Milkweed as monarch host plant, pollinator value, and native range in eastern U.S.
- University of Connecticut — https://homegarden.cahnr.uconn.edu/factsheets/milkweed/Supports: Genus identity, sap toxicity, and milkweed species in northeastern North America.
- U.S. Forest Service — https://www.fs.usda.gov/wildflowers/plant-of-the-week/asclepias_syriaca.shtmlSupports: Common milkweed within the genus and species occurrence in the Americas.
- U.S. Fish and Wildlife Service — https://www.fws.gov/story/spreading-milkweed-not-mythsSupports: Monarchs lay eggs on milkweed.
- Massachusetts Horticultural Society — https://www.masshort.org/blog/milkweedSupports: Common milkweed as an ornamental and monarch host plant.