swamp milkweed

noun

a coarse milkweed, Asclepias incarnata, growing in swampy places from eastern North America to Colorado, having ball-like clusters of rose-purple flowers.

Origin of swamp milkweed

An Americanism dating back to 1855–60

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018