Aquatic Milkweed
Asclepias perennis
Photo Citations
Naturedigger would like to thank the following individuals for their contributions to the aquatic milkweed (Asclepias perennis) identification slide:
Flower image provided by: R.W. Smith - Lady Bird Johnson Wildflower Center (cropped)
Leaf/stem images provided by: Jeff Ausmus, Ausmus Ranch- (cropped)
Pod image provided by: Ray Moranz, Xerces Society - (cropped)
Asclepias perennis Profile
Common Name(s):
aquatic milkweed
white swamp milkweed
Scientific Name:
Asclepias perennis
Native Range:
AL, AR, FL, GA, IL, IN, KY, LA, MO, MS, SC, TN, TX
USDA Symbol:
ASPE
Habitat:
• saturated soils
• floodplains
• marshes
• wetlands
• cypress swamps
• ditches
• streams
Growing Conditions:
• partial sun to medium shade
• abundant organic matter
• consistently moist soil, but not long-term standing water
Plant Height:
1-2 feet (30.5-61 centimeters)
Stem Description:
• light green to purplish green
• unbranched, erect flowering stems
• nearly glabrous
Leaf Description:
• 2.5-5 inches (6.35-13 centimeters) long
• 0.25-1.5 inches (0.5-4 centimeters) wide
• upper leaf surface is medium to dark green
• lower leaf surface is light to medium green
• narrow petioles that are light green to purplish green and grooved along the upper side
• linear, elliptic
• leaf tips taper gradually to acute points
• leaf bases are wedge-shaped
• leaf vein and underside are dull green
• prominent mid-vein
Leaf Arrangement:
• opposite
Leaf Margin:
• entire
Leaf Surface:
• glabrous
Flowering Period:
• May-November
Flower Description:
• pinkish white corollas, hoods and horns
• one or more umbels produced in the axils of the upper leaves
• each umbel has 20-25 flowers
• mildly fragrant
Pod Description:
• 2.5-3 inches (6.35-7.6 centimeters) long
• 0.5-1 inch (-2.5 centimeters) wide
• smooth and glabrous
• immature pods are erect, but droop downward at maturity to release seeds
Other Information:
• seeds are able to float on water for extended periods of time
• this species has special value to native bees
To Locate and Purchase Seeds (when available):
Xerces Society Milkweed Seed Finder
Milkweed and Wildflower Vendors
For More Information About This Species Visit:
Xerces Regional Milkweed Guides
Lady Bird Johnson Wildflower Center