Milkweed Plant Details
Swamp Milkweed – Asclepias incarnata
Swamp milkweed (Asclepias incarnata) is a native perennial and one of the most important plants you can grow in your garden. Monarch caterpillars can only eat milkweed and a few close relatives; they depend on it to lay their eggs and raise their young. Swamp milkweed grows as a clump and does not run like common milkweed.
Why Plant Swamp Milkweed?
Swamp milkweed blooms in midsummer, attracting butterflies, bees, and other pollinators with its clusters of vanilla-scented pink flowers. In fall, the seed pods split open, and the fluffy seeds float off on the wind. Monarch butterflies lay their eggs on the leaves. Once the eggs hatch, the caterpillars feed on the plant. Planting native milkweed helps restore natural habitats and supports local ecosystems.
How to Grow a Healthy Swamp Milkweed Plant
Swamp milkweed grows along ponds, streams, and wet meadows; it doesn't need a swamp to grow. It can also thrive in moist garden soil. It requires full sun to light shade.
Swamp milkweed is hardy in USDA zones 3 through 9 and grows to about 3 to 5 feet tall and 3 feet wide. Water it regularly the first season and during dry spells. Avoid using pesticides near your milkweed plant, as chemicals can harm monarch caterpillars and beneficial insects. The milky sap can irritate the skin and eyes, so wear gloves when you handle it, and keep pets from chewing on it.
Milkweed Plants for Sale: Best Uses in Your Garden
Plant swamp milkweed in pollinator gardens, meadow plantings, borders, or pond edges, alongside native perennials and flowering plants. Space plants about 18 to 24 inches apart, and plant a few together. A group is easier for monarchs to find than a single plant. A 5-pack is a good place to start: set them about 18 inches apart, and by their second summer they’ll fill in a patch about 4 feet across. Milkweed also needs pollen from another plant to set seed pods, so with five you’ll get more pods and new seedlings than you would from one or two. Our swamp milkweed plants for sale come in packs of 5, 10, or 25 in regular pink or Bubble Gum Pink variety.
This plant ships bare root. Plant it soon after it gets to you. Soak the roots for an hour or two, spread them out in the hole, and cover the top of the roots with about an inch of soil. Water it generously. Don't worry if you don't see anything for a while. Milkweed is one of the last plants to come up in spring, sometimes not until late May or June, so mark the spot so you don't dig it up by mistake.
Planting & Growing Information
Ships: Ships now
Planting zone: 3-9
Height at maturity: 3-5 feet
Water needs: Moderate to high
Sun or shade: Full sun or partial shade
Bloom season: Midsummer
Care: Plant swamp milkweed in moist soil; water regularly; avoid pesticides and fertilizers to preserve monarch butterflies.
Exposure: Swamp milkweed prefers full sun, at least 6-8 hours of sunlight daily.
Plant attributes: Vanilla-scented flowers, host to monarch caterpillars and butterflies, forms tidy clumps instead of runners.
Learn more about milkweed varieties and their care with our Milkweed guide. You can also explore our collection of pollinator plants to create a garden that attracts butterflies, bees, and other beneficial pollinators.
