This shorter milkweed is noted for its unusual green-and-purple flowers (viridis means “green”) and curved seed pods that resemble antelope horns (another common name is "green antelope horn").  It has an upright, open form and large, smooth leaves with wavy margins.  It grows best in full sun and a variety of dry-to-medium, well-drained soils, and it tolerates light shade and rich or poor soils.  Once established, it requires little water.  
 
This species is one of the first milkweeds to bloom in the Ohio Valley starting in May or June.  It produces baseball-sized umbels of tiny flowers.  Each flower has five thick, pale green petals that surround five purple “hoods.”  According to the Nature Institute, flowering milkweeds have large amounts of concentrated nectar that attract insects day and night.  The flowers have a highly complex system for pollination.  Nectar is stored inside green milkweed’s little purple hoods.  Pollen resides within grooves between the hoods.  The only way the pollen can escape is when a foraging insect’s leg slips into the groove and pulls the package of pollen from its chamber.  The pollen must then be transferred to another flower in the same way, with the insect's leg slipping through the same groove to deposit pollen deep within the flower.
 
Native habitats include dry areas, prairies, pastures, roadsides and ditches, disturbed ground, and areas with little vegetative competition.  Green milkweed is ideal for sunny borders, cottage and butterfly gardens, and naturalized areas.  
 
Plant Characteristics:
Grows 18-24” tall and 18” wide.
 
Prefers full sun but will grow in light shade.
 
Prefers dry-to-medium well-drained soils, including chalk, clay, loam, and sand.  
 
Flower umbels are 3-5” wide with 10 or more flowers per umbel, blooming from May to June.  Light green seed pods containing 50-100 seeds with white fluff turn straw colored as they mature.  
 
Green leaves alternate on multiple sturdy stems that emerge from the root crown.  A milky, sticky sap exudes from broken plant parts.  Green milkweed has a deep tap root.
 
Wildlife Value:
Host plant for 12 species of Lepidoptera larvae, including specialists monarch butterfly, and milkweed tiger, unexpected cycnia and Isabella tiger moths.  Honey bees and native bees are drawn to the nectar, and many other insects feed on the plant.  
 
Medicinal, Edible, and Other Uses:
Milkweeds contain cardiac glycosides, which are have been used to treat heart conditions but are potentially poisonous to humans.