Native to the southeastern United States, Aquatic Milkweed live in swampy regions. They require consistently moist, neutral pH soils in full sun to survive. Their flowers attract butterflies, although their larva may prey on these.
Asclepias perennis (Aquatic Milkweed)
Hardiness Zones: 6-9, tolerates temperaturs as low as -23 degrees Celsius (-10 degrees Fahrenheit)
Height: 45-60 centimeters (18-24 inches) tall
Diameter: up to 30 centimeters (12 inches) wide
Growth Rate: moderate
Root System: taproot
Tolerates: consistently wet conditions
Problems (major): none
Problems (minor): host to some butterfly and moth species
Poisonous: Potentially toxic, the sap may cause dermatitis in some.
Soil requirements: requires consistently wet soils, survives in water, grows in light/sandy and medium/loamy soils, tolerates neutral soils (5.0-7.5 pH)
Air requirements: not sufficiently researched
Watering requirement: requires consistently wet conditions
Sun requirement: requires full sun
Leaf structure: arrangement opposite, linear to elliptic, petiolate, petioles to 2 centimeters (1 inch) long, leaves to 13 centimeters (5 inches) long, undersides green
Stem structure: dark purple-green, up to 3 umbels per stem
Flower structure: umbels, glabrous, flat panicles, peduncles to 2 centimeters (1 inch) long, individual flowers to 4 millimeters long by 2 millimeters wide, flowers
white with 5 petals with white hoods
Flowering frequency: May-September
Freshwater/Saltwater native: freshwater
Location (Pond, Stream, River, Lake, Sea, Ocean): pond, stream, marsh, floodplains
Monocot or Dicot: Dicot
These can divide by rhizomes. These survive in marshy, consistently wet soils.
Aquatic Milkweed attracts butterflies and other pollinators.
White flowers and foliage of A. incarnata (uploaded 11 August 2009 by Fabio Alessandro Locati at the Botanical Garden Hanbury at Ventimiglia, Italy)
I do not own the rights of these images; all credit goes to its original creator(s).