Native Plant Trust

Asclepias incarnata

swamp milkweed, rose milkweed


Swamp milkweed, also known as rose milkweed, is one of the showier milkweeds, with large pink flowers that attract a wide variety of pollinators and closely co-evolved insects. This species is eponymously known for growing in moist locations, but will thrive in average garden soil if babied a little bit in its first year. Swamp milkweed is perfect for naturalizing, restoration projects, and lowland garden beds.

Click on these links to read in detail:  General Description | Benefits | Ecology | References


Height: 24-42 in
Spread: 12-24 in
Hardiness Zone: 3-9


Bloom Color: Pink

Characteristics & Attributes

Cultivation Status
Species
Exposure
Sun
Part Shade
Soil Moisture
Average
Wet
Ecoregion
(83) Eastern Great Lakes Lowlands
(59) Northeastern Coastal Zone
(84) Atlantic Coastal Pine Barrens
(82) Acadian Plains and Hills
(58) Northeastern Highlands
Ornamental Interest
Summer Bloom
Attracts Wildlife
Host Plant
Other Pollinators/Wildlife
Attracts Butterflies
Attracts Bees
Tolerance
Deer/Rabbit Resistant
Additional Attributes
Low Maintenance


North American Distribution


General Description

Bloom Description: The blooms consist of a cluster (umbellate raceme) of mauve to occasionally white flowers with five reflexed petals surrounding an elevated central crown. Blooms from late June to early August.

Growth Habit & Shape: At maturity these plants will form tall clumps, and may spread by seed if conditions are favorable.

Soil Preferences: Prefers wet or moist soil conditions, but will survive drought once established in more average-moisture soilis.

Root Description: The roots are fleshy and white, spreading fairly shallowly beneath a short, persistent caudex.

Garden Uses: Swamp milkweed works beautifully in mixed borders and meadow plantings. They can also be seeded or planted in wet roadside ditches and pondside for a stunning visual effect.

Best Management & Maintenance: This is a low-maintenance plant; cut back the previous season's stalks in early spring if desired. If planting in soil that is not consistently moist, water as needed for the first few years to help individuals establish drought-resilience.

Common Problems: When stressed by drought or root-bound in containers, these plants are susceptible to infestation by aphids along the stems, which may kill young, small plants. Remove manually, with neem oil in the early morning or evening, or spray with a dilution of dish soap and water.

Benefits

Ornamental Benefits: This is a plant with a lot of ornamental value, not the least being the butterflies and bees it is certain to attract. Large pink flowers and smooth dark green leaves mix well with other textures, and the beautiful geometry of the vertical standing seed heads provide further visual interest through late fall.

Wildlife Benefits: Like other milkweeds, swamp milkweed attracts large numbers of pollinators, particularly native bees. 12 species of butterfly and moth use this plant as larval host, including the Monarch butterfly.

Other Practical/Environmental Benefits: Takes up space that might otherwise be filled by weeds!

Ecology

Habitat:
In the wild, Asclepias incarnata is found in wet meadows, wetlands, pond edges, ditches, and stream banks.


Response to Disturbance: Though this species prefers consistently moist growing conditions and is severely affected by drought (especially several years in a row), individual plants produce a large quantity of seeds that disperse readily and widely, and that have relatively high germination rates (50-80%). As such, this plant is considered highly resilient to drought and above-ground disturbance. The species is capable of surviving in wet woodlands provided some sunlight, suggesting an ability to survive natural successional changes.

Native State Distributions:
Canada: MB, NB, ON, QC, SKU
USA: AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NY, OH, OK, PA, RI, SC, SD, TN, TX, VA, VT, WI, WV


Wetland indicator status: OBL

References

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swamp milkweed - Asclepias incarnata from Native Plant Trust
swamp milkweed - Asclepias incarnata from Native Plant Trust
swamp milkweed - Asclepias incarnata from Native Plant Trust