Skip to content
TrueNorthBriefQuick, clear answers for curious Canadians
Things

Milkweed

What is milkweed?

· Sarah Mitchell

Key facts

Scientific name Asclepias[1]
Family Apocynaceae[1]
Type Herbaceous perennial flowering plants[1]
Sap Milky[2]
Range North and South America[1]

Milkweed is a genus of herbaceous perennial flowering plants in the dogbane family, Asclepias, known for its milky sap and as a host plant for monarch butterfly larvae. Common species include common milkweed and swamp milkweed. It is native to North and South America.

Context

Milkweed is a genus of herbaceous perennial flowering plants in the dogbane family, Asclepias, known for its milky sap and as a host plant for monarch butterfly larvae [1]. The name refers to the plant's milky sap, and many species are important host plants for monarch butterfly larvae [2]. Milkweed is native to North and South America [1].

Documented claims

  • Milkweed butterflies, including monarch butterflies, rely exclusively on milkweed plants as a food source for their larvae. [1]
  • All milkweeds contain a milky sap that contains cardiac glycosides, which can cause poisoning in humans and animals if eaten. [2]

Questions and answers

Is milkweed poisonous to touch?

The milky sap contains cardiac glycosides, which can cause poisoning if eaten, but there is no indication that touching it is harmful [2].

Why is milkweed important for monarch butterflies?

Monarch larvae appear to feed exclusively on milkweeds, making them essential for the butterflies' survival [3].

Sources

  1. Milkweed | Home Garden Education Office | College of Agriculture, Health ... — homegarden.cahnr.uconn.edu (retrieved August 3, 2026)
  2. milkweed — kids.britannica.com (retrieved August 3, 2026)
  3. Spreading milkweed, not myths — fws.gov (retrieved August 3, 2026)

Sources last checked August 3, 2026. · More in Things