Swamp Milkweed


Swamp Milkweed, Asclepias incarnate, is one of twenty-three species in the genus Asclepias; 22 are native and 1 non-native. In Florida, the milkweeds are the larval host plants for the Monarch butterfly which have seriously declined in population.  Swamp Milkweed is an erect perennial shrub one to two feet in height.  Usually, there are 3 to 6 woody stems growing from a deep tap root 1 to 2 feet deep. Leaves are narrow and long.  Opposite leaves are 2 to 6 inches in length and about ½ inch wide.  Thick white sap flows when a leaf is broken.

Flowers are complex. The plant’s inflorescence, flower arrangement, is cluster of 20 to 30 blooms. The flower stalks all meet at a single point on the upper portions of the stems. This arrangement is called an Umbel. The specimen in the picture is a close up of an umbel.  The corolla has five rose-pink petals that droop downward.  At the middle of the corolla is a large sticky female stigma connected to two fused female pistils. Surrounding the stigma are five curved appendages called hoods.  Hoods are a form of sterile male stamens.  In the walls of the hoods are pollen glands.  Attached to each hood is hook. When a butterfly lands and goes after the pollen glands, the hook traps the pollinator so that a struggle ensues and pollen is dropped on the stigma. The butterfly often loses a leg in the process.

The Swamp Milkweed is found in wetland habitats.  Milkweeds are also in a serious population decline.