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Milkweed Facts

Milkweed Facts


Milkweed is the common name for a group of plants that belong to the Asclepias genus. This genus of plants is named after Asclepius, the god of medicine and healing in ancient Greek mythology. Milkweeds have a long history of being used for medicinal purposes because of the cardiac glycosides found in their tissue.

Milkweed is the host plant for the monarch butterfly. As the monarch larva consumes the milkweed leaves, it also retains the cardiac glycosides making the monarch toxic to predators.

Important Precautions: The following two bullet points are a reminder that milkweed contains toxins in its sap. The monarch butterfly intentionally eats milkweed to become distasteful to protect itself from predators, hence the bright warning colors they feature.

  • If you prune your milkweed plants or take cuttings to supply your monarch larvae with food, please take precautions so that the milkweed sap does not get into your eyes. If this happens, please seek medical attention.
  • Please do not ingest any milkweed plant material. If this happens, please seek medical attention.

There are over 100 species of milkweed in North America and the diversity of foliage and flower color is quite amazing. All milkweeds are herbaceous perennials, meaning they live for more than two years. In fact, most milkweeds will live for several years if cared for properly. Since some milkweeds can't handle freezing temperatures, there are two classifications we like to divide them into:

  • Hardy Perennials - These milkweed species can survive below freezing temperatures in any zone in the United States. They go dormant in the winter months and return each spring.
  • Frost Sensitive Perennials - A few milkweeds fall into this category. You can still grow them anywhere in the United States. However, if you live in a zone that falls between 1 and 9, the plants will die in the winter and you will have to replant from seed in the spring. In zones 10 - 11, these milkweed species will grow year round.

View the USDA Plant Hardiness Zone Map to determine which zone you live in.

Milkweed is a great plant for the garden and provides habitat for many creatures. In addition to being a host plant to the monarch butterfly, milkweed offers many other benefits:

  • Milkweed flowers produce nectar that all butterfly species benefit from.
  • Honey bees take nectar from milkweed flowers. With the decline of honey bee populations in the US, planting milkweed in your garden can help to provide feeding stations as they fly between crop fields and orchards.
  • Hummingbirds often use the floss from milkweed seed pods to line their nests.

If you feel milkweed is right for you, please feel free to browse our listing of available milkweed seeds.