Asclepias perennis Walter
White Swamp Milkweed, Aquatic Milkweed
Asclepiadaceae (Milkweed Family)
USDA Symbol: ASPE
Stem is a dark purplish-green color in contrast to the evergreen color of the leaves. Stands erect to ascending. Leaf arrangement is opposite. Leaf attachment is petiolate with short petioles approximately 2/3 in (1 1/2 cm) long. 3+/- umbels to a stem (Webref 20).
This species can be easily identified before the flowers open because the tips of the corollas are pink creating a large pink spot at the apex of an unopened flower. Leaves are relatively short and narrow. Grows in areas with soils that are continuously wet (Webref 20).
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Plant CharacteristicsDuration: Perennial
Leaf Arrangement: Opposite
Leaf Shape: Elliptic , Linear
Leaf Pubescence: Glabrous
Leaf Margin: Entire
Fruit Type: Follicle
Size Notes: Up to about 32 inches tall.
Leaf: Green, linear to a narrow elliptic, 3-5 in (8-13 cm) long by 1/2-1 1/2 in (1-4 cm) wide. Leaf vein and underside are a duller green.
Flower: Glabrous. Umbels erect with 25 +/- flowers presented as a flat panicle. Tips of the corolla can sometimes be tinged with pink. Corollas, hoods, and horns are usually white or light pink. Horns protrude through the hoods. Corolla reflexes backward. Each flower is approximately 1/8-3/16 in (3-4 mm) long and 1/16 in (2 mm) wide.
Fruit: Follicles pendulous. Smooth, hairless, long 1 1/2 -2 1/2 in (4 - 6 cm) , and narrow 1/2 -1 in (1-2 1/2 cm) wide.
Bloom InformationBloom Color: White , Pink
Bloom Time: May , Jun , Jul , Aug , Sep
DistributionUSA: AL , AR , FL , GA , IL , IN , KY , LA , MO , MS , SC , TN , TX
Native Habitat: Hydrated soils, floodplains, water way margins, marshes, cypress swamps, ditches, and wet lands.
Growing ConditionsLight Requirement: Sun , Part Shade
Soil Moisture: Moist , Wet
BenefitConspicuous Flowers: yes
Value to Beneficial InsectsSpecial Value to Native Bees
Special Value to Bumble Bees
Special Value to Honey Bees
Supports Conservation Biological Control
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
PropagationPropagation Material: Seeds
National Wetland Indicator Status
Web ReferenceWebref 20 - Milkweed Profiles (0) Monarch Watch
Research LiteratureReslit 383 - Population-Genetics of the Rare Asclepias texana and Its Widespread Sister Species, A. perennis (1994) A. L. Edwards and R. Wyatt
Reslit 2278 - Comparative Anatomy and Morphology of Asclepias perennis and Asclepias tuberosa Subspecies Rolfsii (1986) T. W. Lucansky and K. T. Clough
Reslit 2388 - Seed Buoyancy and Viability of the Wetland Milkweed Asclepias perennis and an Upland Milkweed, Asclepias exaltata (1994) A. L. Edwards, R. Wyatt and R. R. Sharitz
This information was provided by the Florida WIldflower Foundation.
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Additional resourcesUSDA: Find Asclepias perennis in USDA Plants
FNA: Find Asclepias perennis in the Flora of North America (if available)
Google: Search Google for Asclepias perennis
MetadataRecord Modified: 2022-09-19
Research By: TWC Staff