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. 2019