How to Grow Swamp Milkweed

Updated: Nov. 20, 2023

Worried about common milkweed taking over your garden? Swamp milkweed, or red milkweed, is less aggressive but good for monarchs.

swamp milkweedCourtesy Mary Kapral
Monarch on swamp milkweed

Plenty of gardeners have heard of common milkweed. Many probably consider it the No. 1 monarch host plant, as well-known for its flowers as for its caterpillar-favorite leaves. While common milkweed is a valuable plant for your garden, it spreads its seeds widely and can be aggressive and difficult to contain. If you don’t want the maintenance but still want to help monarchs and attract other butterflies, there’s another native alternative: swamp milkweed (also known as red milkweed). Here’s why you should add this milkweed plant to your yard.

Check out the ultimate guide to growing milkweed plants for monarchs. Plus, is milkweed poisonous to people and pets?

Swamp Milkweed Care

swamp milkweedCourtesy Cheryl Fleishman
Swamp milkweed is an important nectar source for monarchs and other pollinators

Scientific name: Asclepias incarnata
Zones: 3 to 6
Light needs: Full sun
Soil: Moist to wet or average soils
Size: Reaches 5 feet high and spreads 2 to 3 feet
Grown for: Showy, fragrant midsummer flowers
Foliage: Long, tapered leaves

Learn how to grow native butterfly weed for monarchs.

Benefits of Growing Swamp Milkweed

swamp milkweedCourtesy Bill Neubaum
Milkweed is beloved by adult monarch butterflies and caterpillars

Native to the Midwest and perfect for filling out butterfly gardens, this type of milkweed is less aggressive than common milkweed yet has all the nectar benefits to fuel monarchs along their epic migration journeys. It grows in challenging conditions, but prefers a sunny, moist spot. (Hence the name: swamp.) Like other milkweeds, it doesn’t look like much until it blooms in midsummer. Then you’re treated to bright flowerheads rising five feet in the air. Blooms range from shades of pink to white. You can’t miss them, and neither can the monarch butterflies.

Like the rest of the milkweed family, this plant is a valuable monarch food source. Monarch and queen caterpillars munch on its leaves, while deer tend to leave it alone.

Here’s how to collect milkweed seeds from pods.

Where to Buy Swamp Milkweed

It shouldn’t be too hard to find this plant in its growing zones. Check your local garden center or purchase plants online from reputable retailers. If you prefer to start plants from seed, swamp milkweed seeds are available, too. Ice Ballet dazzles with all-white flowers and darker green foliage, or host the belle of the ball with Cinderella’s fuchsia blooms.

Shop Now

Next, follow the stages of the monarch butterfly life cycle.