PROTECTING WISCONSIN'S BIODIVERSITY

 
 
   
 
Scientific Name Common Name Global Rank State Rank Federal Status WI Status

Green Milkweed (Asclepias hirtella)

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Photo by Kevin Doyle

 

Counties with Mapped NHI Occurrences

Green Milkweed (Asclepias hirtella), a Wisconsin Special Concern plant, is found in wet to dry prairies. Blooming occurs from June through August, fruiting July through September. The optimal identification period for this species is in June through September.

 
 
 

Green milkweed is an erect forb up to 1m tall, with numerous umbels spread along upper half of stem, on short (1-2cm) peduncles. Its green petals are reflexed, separated from the hood, and sometimes have a pink hue. It is lacking projections from hoods, or horns. Fruits are short, hairy pods without warty bumps. Leaves are alternate or sub-opposite, narrow linear, hairy, and often fold upward.

Tall green milkweed can be distinguished from other milkweeds by its narrow leaves and the often drooping, umbels that are often greenish-white on short pedicels, and a column separating the corolla from the base of the hoods. Of the other milkweeds that are found in wet or mesic prairies, A incarnata is taller and has bright pink flowers, A sullivantii has wider, smooth leaves with no petioles, and A syriaca has wide, hairy leaves. A viridiflora may look similar but is found in dry prairies, has slightly wider leaves that are not as folded along the midvein, and has smaller (less than hemisperical) umbels.

Blooming occurs June through August, fruiting July through September.

Perennial. The optimal identification period for this species is June through September.

Associated species include Phlox pilosa, Tradescantia, Allium cernuum, Eryngium yuccifolium, Liatris pycnostachya, and Baptisia leucophaea.

Green milkweed is found in wet to dry prairies.

Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.

Avoid broadcast spraying of herbicides and use care with spot spraying.

Avoid site preparation that heavily disturbs herbaceous ground layer and soil, including bulldozing and furrowing, as well as grubbing and stump removal.

Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.