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Woodland Bluegrass (Poa sylvestris)

Life history

Species overview

Woodland Bluegrass (Poa sylvestris), a Wisconsin Special Concern plant, is found in very moist streambanks and in mesic forests. Blooming occurs mid-May through June; fruiting occurs June through August. The optimal identification period for this species is early June through late July.



  • Distinguishing characteristics: Plant tufted; lemmas with 5 veins and webbed at base; lower panicle branches in sets of about 5 or more; ligule about 1 mm long.
  • Flower characteristics: Panicle open, 10 to 20 cm long, much longer than wide; branches in sets of 4 to 8, lower ones drooping; spikelets 2- to 4-flowered, 3 to 4 mm long;
  • Fruit characteristics: Caryopsis with adherent pericarp; lemmas with 5 veins, 2.5 to 3 mm long, webbed at base, pubescent on keel and marginal nerves.
  • Leaf characteristics: Leaves 2 to 6 mm wide, lax and soft, mostly along the stem; sheaths glabrous (rarely pubescent); ligule about 1 mm long.


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


  • Growth form: Graminoid
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Ulmus americana, Acer saccharum, Fagus grandifolia, Quercus rubra, Ostrya virginiana, Caulophyllum thalictroides, Hydrophyllum virginianum, Erythronium albidum, Carex hirtifolia, Adiantum pedatum, Geranium maculatum, Dentaria laciniatum, Sanguinaria canadensis, Podophyllum peltatum.

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 Woodland Bluegrass (Poa sylvestris). 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 Poa sylvestris in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS1
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 very moist streambanks and in mesic forests.
  • Soils: Moist, often calcareous soils.

Natural communities

This table lists the natural communities that are associated with Woodland Bluegrass. 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).

Natural communities score
Southern Mesic Forest 3
Algific Talus Slope 1

Ecological landscapes

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

Map of the Ecological Landscapes of Wisconsin.

Ecological landscape score
Southeast Glacial Plains 2
Western Coulee and Ridges 3

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 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 high forest canopy cover; this species requires shaded habitat conditions.


Woodland Bluegrass Photo.

Photo © Emmet Judziewicz.

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: Wednesday, May 05, 2021
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