Swamp Milkweed: The Third Milkweed Species

Milkweeds are just beginning to bloom in Eliza Howell Park in the third and fourth weeks of June. I find myself paying special attention this year to Swamp Milkweed, a species that I have not written about before.

In fuller bloom, Swamp Milkweed looks like this.

Previous milkweed-related posts have focused on Common Milkweed and Butterfly Weed, both more widespread in the park. Based upon my most recent observations, Swamp Milkweed is, however, a little more common than I had thought.

In this collage, Butterfly Weed is on the top left, Common Milkweed is bottom left, and Swamp Milkweed is on the right.

As its name indicates, Swamp Milkweed grows best in wetter areas. As writers sometimes say, it likes to grow where “it can get its feet wet.”

The best area for finding it in Eliza Howell is in the wet meadow, near what I refer to as the toad breeding pond. Here is a small patch, not yet in bloom, that I have been watching.

All three of these milkweed species are host species for Monarch Butterfly larvae. And Swamp Milkweed, like Common Milkweed, has the white sticky sap that is the basis for the family name. (Butterfly Weed is the family exception in that it does not have this “milk.”)

While Swamp Milkweed is selective in its growing environment, it is geographically widespread. (This map is from the USDA.)

Perhaps because it grows primarily in a different part of park from the major summer wildflower displays, it doesn’t usually get visited as frequently as the other two milkweed species. This year I am definitely enjoying getting to know it better.

The leaves are narrower than those of the Common Milkweed, but larger than Butterfly Weed leaves.

There are other milkweed species that grow in Michigan, but to date I am aware with only three in Eliza Howell Park. As I am always learning more about park flora and fauna, perhaps one of these days I will discover a fourth local species!