To see a field of common milkweed in midsummer — a sea of a thousand nodding pink flower heads — you would not imagine that anything could ever stand in the way of the genus Asclepias.
Yes, common milkweed (Asclepias syriaca), the most widespread milkweed east of the Rocky Mountains, can colonize disturbed sites and form impressive stands. But it is an exception among the more than 90 recognized North American species of milkweed, many of which often find it not so easy to continue making themselves at home.
“The milkweed is a displaced citizen in its own land,” writes Eric Lee-Mäder in the opening of his new book, “The Milkweed Lands: An Epic Story of One Plant, Its Nature and Ecology.” “Where once it owned the continent, it’s now a kind of vagrant, occupying the botanical equivalent of homeless encampments.”
As one example, he cites 2012 research, by