Red Milkweed

Red Milkweed is a fast-growing, wet soil-loving, Wisconsin native perennial with beautiful deep pink flowers that attract many insects. Monarch butterflies use it as a host plant. Although it can tolerate moderate moisture and even heavy clay, it’s normally found in marshes, swamps, and near ponds, lakes, and waterways.

Pretty flowers, a fast growth rate, and a love of wet soil make Red Milkweed a gem for wetland landscapes and gardens.

You may also know Red Milkweed as Swamp Milkweed.

We may grow this plant in multiple sizes, including larger sizes available for pick-up in-store. But we also have it available in smaller plug sizes for purchase online. Plugs are also available in-person.

Red Milkweed can be used to naturalize a wetland habitat and also makes a wonderful addition to a wetland garden or a rain garden.

Although this species prefers wet soil, once it is established it can adapt to soil with average moisture.

Floating Eco-Islands
These are essentially gardens built on top of water. They’re often used in landscapes or properties with water like small ponds, rivers, and lakes. Since Red Milkweed is common in marshes, swamps, and waterways, it’s also commonly considered for use in a floating eco-island.

Most notably a host to Monarch (Danaus plexippus) and Queen (Danaus gilippus) butterflies. A Monarch will lay a tiny egg (about the size of a large grain of sand) on the underside of Milkweed leaves. The caterpillar will feed exclusively on the leaves upon hatching until it matures enough to form a chrysalis. Adults also feed on nectar from Milkweed (as well as other) flowers. Healthy host plant populations are essential to the continuation of Monarchs as their life cycle depends on Milkweed. Read more about how to attract Monarch butterflies to your yard.

Several Milkweed beetle species rely on Milkweed to complete their life cycle. They are all herbaceous and generally not considered a nuisance. Eggs are laid at or near the base, the larvae hatch and burrow beneath the ground to feed on the milkweed’s roots. The adult pupates and eats the leaves, buds, and flowers. If you observe them in your yard and only have one Milkweed, consider planting more to offset what these beetles feed on.

Monarch caterpillars and Red Milkweed Beetles will bite through the leaf veins near their feeding site to stop the flow of latex. This allows them to feed on the leaves without ingesting too much latex. If the latex is left to flow freely, it can stick to their mouthparts rendering them immobile and unable to feed.

Just like Monarchs, Milkweed beetles are toxic because they ingest the toxic substance in Milkweed.

We are a participating nursery in the Safe for Monarchs program, which aims to connect gardeners with monarch-supporting plants. We aim to help grow plants in ways that are safe for adult monarchs as nectar sources and for monarch caterpillars as host plants.

Learn more about the Safe for Monarchs program (wimonarchs.org)

Red Milkweed is a shorter-lived species. When planted in a good site it should last multiple seasons but do not be surprised if it only persists for 1-3 seasons. It may need to be replanted depending on how long it lives.  They may self-perpetuate and spread by seed if planted in an optimal site.

Water your plants if the soil is in danger of drying out, such as during the hottest part of summer or drought. If planted in wet soil, Red Milkweed requires little, if any, maintenance.

Propagation is best done by seed as Red Milkweed has a long taproot.

Few issues will arise with Red Milkweed if planted in the right location. Aphids are commonly found on Milkweed. That said, it can continue thriving and flowering despite aphids. The aphids can be sprayed with soapy water or blasted with a hose. Only do this if the plant is showing signs of stress and be sure to identify any Monarch eggs or caterpillars before doing so as any treatment will cause harm to our friends.

The presence of some aphids can help to boost populations of beneficial insects in the environment as they are a food source for some predatory insects such as beetles and flies. Ladybugs are a widely known predator of aphids. Keeping aphids around can boost the amount of beneficial predatory insects by providing them with food. These predatory insects can then also target other pests in a garden. While there are situations in which treatment would be the best course of action, Milkweed is rather tolerant of aphids and should be left alone as long as there is no visible effect on the plant’s fitness.

Name: Genus, Asclepias, named for Greek God of medicine Aesculapius due to Milkweed’s historical use as a medicinal plant. The species name comes from the Latin word “carn” which refers to a light pink, flesh-color hue that the leaves and stem can take on later in the growing season.

Historical Uses: Every part of Milkweed is poisonous. Large quantities can induce vomiting as well as cause weakness and spasms. The insects that feed off of milkweed are also poisonous. That said this plant has a myriad of uses, medicinal, edible, and practical.

The stems flowers and leaves can all be eaten after being boiled. An infusion of the roots was used to pass parasitic worms as well as a plethora of other uses the sum of which justify it being named after the actual Greek god on medicine.

Bark fiber can be used as cordage. Seed fluff is water repellant and can be used as stuffing for pillows and has been used inside life jackets. Latex in the leaves can be turned into rubber. Has much potential.

Want to learn more about the entire genus Asclepias? See how all the Milkweed plants stack up against one another in our Milkweed Comparison.

To naturalize an area, it would be good to pair Red Milkweed with other wetland plants that include:

• American Elderberry (Sambucus canadensis)
• Buttonbush (Cephalanthus occidentalis)
• Silky Dogwood (Cornus amomum)
• Witherod Viburnum (Viburnum cassinoides)
• Winterberry (Ilex verticillata)
• Tamarack (Larix laricina)
• Lady Fern (Athyrium filix-femina)
• Spotted Joe-Pye Weed (Eutrochium maculatum)
• Harlequin Blue Flag (Iris versicolor)
• and so many more!