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Butterfly Gardening and Habitat Program

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Swamp Milkweed - Asclepias incarnata


Appreciative of damp locations, swamp milkweed plants will increase in size by sending out underground stems, called rhizomes, which produce clumps of plants. The rhizomes do not spread far, resulting in a garden plant that is thick and eye-catching to butterflies as well as other pollinators.

Importance as a caterpillar food source: Like all milkweeds, swamp milkweed is an important food source for Monarch caterpillars.

Importance as a butterfly nectar source: Once established in the garden, swamp milkweed plants will produce a large number of showy blooms per plant that are attractive to a variety of butterflies. The large number of blooms per plant make swamp milkweed an essential butterfly garden plant.

The current rating for swamp milkweed is:

Garden Rating
Nectar Rating
Caterpillar Rating

If you have experience growing swamp milkweed, we would like your opinion. Let us know how it performed in your butterfly garden. Your comments will help other butterfly gardeners in your region to create better butterfly gardens:


Swamp Milkweed Cultural Requirements
USDA Hardiness Zone 3 to 9
Bloom Period July to August
Bloom Color White to light pink
Plant Height 24 inches
Plant Spread Varies
Light Exposure Sun to part shade
Soil Moisture Moist to wet
Animal/Pest Problems Deer resistant, aphids may be a problem




Eastern Tiger Swallowtail on swamp milkweed

Swamp Milkweed


Comments from NABA Members

Swamp milkweed plants are easiest to establish from seed

 Native Range for Swamp Milkweed (Asclepias incarnata)


Baltimore Checkerspot on swamp milkweed



©2008 North American Butterfly Association