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Western Jacob's Ladder (Polemonium occidentale ssp. lacustre)

Life history

Species overview

Western Jacob's Ladder (Polemonium occidentale ssp. lacustre), a Wisconsin Endangered plant, is found in open cedar swamps, as well as cold, seeping calcareous conifer swamps. Blooming occurs throughout July; fruiting occurs throughout August. The optimal identification period for this species is throughout July.

Synonyms: Polemonium occidentale var. lacustre


  • Distinguishing characteristics: Inflorescence a compact panicle, the pedicels at peak flowering shorter than the calyx; flowers in the summertime.
  • Flower characteristics: Flowers mostly blue, crowded in a typically elongate and somewhat thyrse-like inflorescence; corolla 10 to 16 mm, fully as wide, lobes longer than the tube; stamens about equalling or a little shorter than the corolla; style conspicuously surpassing the stamens.
  • Fruit characteristics: Seeds 1 to 10 per locule, sometimes becoming mucilaginous when wet.
  • Leaf characteristics: Leaves alternate, pinnately compound or very deeply pinnatifid; lower leaves with 1 to 27 leaflets, 1 to 4 cm, the middle and upper smaller.


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


  • Growth form: Forb-erect
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Comments: Associated Species: Larix laricina, Thuja occidentalis, Picea mariana, Valeriana sitchensis ssp. uliginosa, Carex tenuiflora, C. gynocrates, C. lacustris, Saxifraga pensylvanica, Calla palustris, Equisetum fluviatile, Alnus rugosa.

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 Western Jacob's Ladder (Polemonium occidentale ssp. lacustre). 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 Polemonium occidentale ssp. lacustre in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG5?T2Q
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 open cedar swamps, as well as cold, seeping calcareous conifer swamps.
  • Soils: Wet, sometimes calcareous soils.

Natural communities

This table lists the natural communities that are associated with Western Jacob's Ladder. 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
Northern Wet-mesic Forest 3
Northern Tamarack Swamp 3

Ecological landscapes

This table lists the ecological landscape association scores for Western Jacob's Ladder. 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
North Central Forest 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 site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.
  • 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 partial canopy to encourage woodland species; avoid closed-canopy conditions.
  • Avoid rapid and dramatic reductions in canopy cover or basal area in wet areas to reduce risk of swamping.
  • Minimize disturbance to hydrology, including soil disturbance from rutting.


Western Jacob's Ladder Photo.

Photo © Stephen L. Solheim.

Western Jacob's Ladder Photo.

Photo © Stephen L. Solheim.

Western Jacob's Ladder Photo.

Photo © Stephen L. Solheim.

Western Jacob's Ladder Photo.

Photo © Stephen L. Solheim.

Western Jacob's Ladder Photo.

Photo by  staff, Wisconsin DNR.

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