What is Milkweed and Why is it Important?

If you talk to anyone who knows about butterflies, especially the Monarch butterfly, they will tell you to plant more milkweed. With overmonarch on milkweed 100 species of milkweed in North America, it’s hard to figure out exactly which ones to plant, when to plant them and where to plant them. There’s a lot of guesswork when being told to plant milkweed but let’s take the guesswork out. Follow along with our series about milkweed over the next month or so to learn why you should plant it, how you should and what it takes to keep it going.

Out of the 100 or more species of milkweed found in North America, only about one-fourth of them are known to be host plants for monarch butterflies according to the U.S. Forest Service. Since Monarch butterflies only lay eggs on milkweed plants, they need milkweed to thrive. But which type of milkweed you may ask.

Here is a list of milkweed plants that will grow in the Midwest and be a host to Monarchs.

  • Asclepias incarnata/ Swamp Milkweed
  • Asclepias sullivantii/ Prairie Milkweed
  • Asclepias syriaca/ Common Milkweed
  • Asclepias tuberosa/ Butterfly Milkweed
  • Asclepias verticillate/ Whorled Milkweed

These five types of milkweed are ones that are able to grow in Dickinson County and will also help monarch butterflies. We will go into why milkweed is the only host plant for Monarchs in next week’s post. This one is all about milkweed.

Why is it called milkweed? The main reason is because of the milky, white sap that is in the plant. Cut off a leaf or cut down the stalk, it will leak out this white substance. This substance contains latex and other chemicals that give the plant a bitter taste. They produce seeds in pods and that will pop open and show the feathery white hairs called floss that will get blown in the wind. The little brown seeds are then attached to the floss and float off in the wind. This is how the seeds are spread.

During World War II, millions of pounds of that milkweed seed floss were collected to fill life jackets and other equipment. This floss is still used today as a hypo-allergenic filling in pillows and comforters.

Milkweed used to grow wherever the seeds could land. A lot of those spots would have been roadsides and in fields where there are now agricultural practices being conducted. Many farmers and other people have become accustomed to spraying weed killers to get rid of the milkweed before it has the chance to go to seed. Five species of milkweed common in our region are listed as threatened or endangered on a federal or state basis now. This has led to a severe loss in habitat for monarch butterflies.

Common milkweed is the most common milkweed that doesn’t need a specific type of environment to grow. The other types of milkweed need a specific environment to thrive. This means if you find milkweed on the side of the road, it’s likely common milkweed. Take a look at it to see if you can find any monarch eggs or even a grown monarch butterfly but remember to leave it there. That milkweed plant is its home.


Resources to help:

Xerces Society Native Milkweed PDF

U.S. Forest Service Monarch Habitat