PROTECTING WISCONSIN'S BIODIVERSITY

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

Dwarf Milkweed (Asclepias ovalifolia)

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Photo by Eric Epstein

 

Counties with Mapped NHI Occurrences

Dwarf Milkweed (Asclepias ovalifolia), a Wisconsin Threatened plant, is found in oak barrens, open pockets within pine barrens, periodically brushed areas, and rights-of-way. Blooming occurs early-June through early-July, fruiting late-June through late-August. The optimal identification period for this species is throughout June.

 
 
 

Dwarf milkweed is an erect forb, 20-60cm tall, with one terminal flower head with one or two additional flower heads in the upper part of plant. The flowers are small, star-shaped, and cream to greenish-purple in color. Petal lobes are 5-7mm long, hoods 4-5mm. Its stem is less than 3mm thick. Fruits are thinly hairy pods. Leaves are opposite, in 4-6 pairs, firm, lance, oblong or elliptica, and 6-10cm long, petioles are 1-8mm long.

It can be distinguished from other milkweeds by its small, delicate stature. The flowers of A ovalifolia are 8-12mm long (vs 10.5-15mm in A syriaca) and the stem is less than 3mm thick (vs 3-5mm thick in A virdiflora).

Slender rhizome. Blooming occurs early-June through early-July, fruiting late-June through late-August.

Perennial. The optimal identification period for this species is throughout June.

Associated species include Pinus banksiana, Quercus ellipsoidalis, Asclepias amplexicaulis, Coreopsis palmata, Aster sericeus, Andropogon gerardii, Sorghastrum nutans, Anemone patens, Helianthus occidentalis, Euphorbia corollata, and Hieracium longipilum.

Dwarf milkweed is found in oak barrens, open pockets within pine barrens, periodically brushed areas, and rights-of-way.

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.

Prescribed burns and/or brushing may be beneficial, dependent on local site conditions and burn frequency. Rotational burns with annual unburned refugia may be preferred.

Maintain and restore open habitat through selective clearing and brushing.

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.