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:


USDA Symbol:




• 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 


Grow Milkweed Plants


For More Information About This Species Visit:


Xerces Regional Milkweed Guides 


Lady Bird Johnson Wildflower Center


Illinois Wildflowers