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Contact information
For information on Wisconsin's rare plants, contact:
Kevin Doyle
608-416-3377

Dwarf Milkweed (Asclepias ovalifolia)

Life history

Species overview

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 occurs late June through late August. The optimal identification period for this species is throughout June.

Synonyms: None

Identification

  • Distinguishing characteristics: Distinguished from other milkweeds by its small, delicate stature. For example, the flowers of A. ovalifolia are 8 to 12 mm long (vs. 10.5 to 15mm in A. syriaca) and the stem is less than 3mm thick (vs. 3 to 5mm thick in A. virdiflora).
  • Flower characteristics: One terminal flower head with one or two additional flower heads in the upper part of plant; flowers small, star-shaped, cream to greenish-purple in color; petal lobes 5 to 7 mm long, hoods 4 to 5 mm.
  • Fruit characteristics: Thinly hairy pods.
  • Leaf characteristics: Opposite, in 4 to 6 pairs, firm, lance, oblong or elliptica, 6 to 10 cm long; petioles 1 to 8 mm long.

Phenology

  • Blooming phenology: early June through early July
  • Fruiting phenology: late June through late August
  • Optimum time to identify: The optimal identification period for this species is throughout June

Other

  • Growth form: Forb-erect
  • Vegetative reproduction: Slender rhizome
  • Life cycle: Perennial
  • Comments: Associated Species: Pinus banksiana, Quercus ellipsoidalis, Asclepias amplexicaulis, Coreopsis palmata, Aster sericeus, Andropogon gerardii, Sorghastrum nutans, Anemone patens, Helianthus occidentalis, Euphorbia corollata, Hieracium longipilum.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Dwarf Milkweed (Asclepias ovalifolia). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Asclepias ovalifolia in the Natural Heritage Inventory Database as of July 2015.


Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS3
Global RankG5?
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in oak barrens, open pockets within pine barrens, periodically brushed areas, and rights-of-way.
  • Soils: Sandy soils.

Natural communities

This table lists the natural communities that are associated with Dwarf Milkweed. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Dwarf Milkweed. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.
  • 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.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Maintain and restore open habitat through selective clearing and brushing.
  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).

Photos


Dwarf Milkweed  Photo.

Dwarf milkweed (Asclepias ovalifolia) in jack pine, Hills oak barrens with black cherry, choke cherry, bracken, Kentucky bluegrass.

Photo by Andy Clark, Wisconsin DNR.

Dwarf Milkweed  Photo.

Dwarf milkweed (WI Threatened) reaches its Wisconsin range limits in the barrens of the Northwest Sands ecological landscape.

Photo by Eric Epstein, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo by Eric Epstein, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo by Armund Bartz, Wisconsin DNR.

Dwarf Milkweed  Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Dwarf Milkweed  Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Dwarf Milkweed  Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.

Dwarf Milkweed  Photo.

Photo © Barbara Delaney.


Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Friday, August 10, 2018
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition