Friends often ask, and I cover this topic extensively in my Monarch programs, “What is the best milkweed to plant in our region?” Without a doubt, the two most important and productive are Common Milkweed (Asclepias syriaca) and Marsh Milkweed (Asclepias incarnata).
Marsh Milkweed also goes by the name Swamp Milkweed, but Marsh sounds so much more appealing, don’t you think? Milkweeds already have the suffix weed attached to their names. To some folks, any wildflower that includes the word weed seems invasive, and we don’t want to frighten people from planting our sweet native wildflowers by inferring they are a swamp dweller, too.
Gallery of Marsh Milkweed
When a weed is not a weed – It’s unfortunate that so many of our native beauties end in “weed.” Ironweed, Joe-pye Weed, Sneezeweed, Thimbleweed, Butterfly Weed, and Milkweed are just some examples. Why were these native wildflowers at one time long ago named “weed.” Because the earliest colonists brought from their home countries flowering plants that were beloved and familiar to them, delphiniums and larkspurs, for example. In their new American home gardens, these treasured European plants would have been easily overtaken by our more vigorous American wildflowers.
To return to the topic of milkweed, Common Milkweed spreads both underground and by seed. It’s ideal for dunes, meadows, and fields. Marsh Milkweed is more clump forming and stays relatively close to where you plant it. You can control how much it spreads by deadheading, or not, before the seed heads turn to fluff and sail away. I grow both Marsh Milkweed and Common Milkweed side-by-side. In our garden, the female Monarch does not discern the difference between the two species of milkweeds, she will flit from one to the other, and back again, depositing her eggs all along the way.
Gallery of Common Milkweed
By the way, both A. syriaca and A. incarnata are also the easiest milkweeds to grow in Massachusetts.
A ten-year nation-wide study was recently published. Across the country, Marsh and Common proved to be the most productive, in other words, more eggs were laid on these two species than on any other species of milkweed.
The map provided below is somewhat helpful; I write somewhat with a word of advice. If you click on Massachusetts, for example, not only are Common and Marsh Milkweeds listed but also Purple Milkweed (A. pupurascens), Fourleaf Milkweed (A. quadrifolia), Butterfly Weed (A. tuberosa), Poke Milkweed (A. exaltata), Whorled Milkweed (A. verticillata), and Clasping Milkweed (A. amplexicaulis). We grow a nice patch of Whorled Milkweed and I have never, ever seen a Monarch once visit the foliage or flowers. Purple Milkweed can be very challenging to get started, and Butterfly Weed is not as hardy in our region as are Common and Marsh.
Milkweeds are the only food plant for Monarch caterpillars and also provide nectar to a host of pollinators including many, many species of butterflies, bees, beetles, and even hummingbirds. Plant for the pollinators and they will come.
This is an image from my recent adventure to Cerro Pelon. I am dying to write about the trip, but have had a very full schedule finishing up my film, organizing landscape jobs for the season, and hoping to get the PiPls settled in. The Monarchs in the photo are mud-puddling. Tens of thousands leave the butterfly trees during the heat of the day, sucking up water and much needed nutrients from the mud at nearby mountain streams