western Jacob’s ladder

(Polemonium occidentale ssp. lacustre)

Conservation Status
western Jacob’s ladder
Photo by Katy Chayka
  IUCN Red List

not listed


NNR - Unranked

S1 - Critically Imperiled



Wetland Indicator Status
  Great Plains

FACW - Facultative wetland


FACW - Facultative wetland

  Northcentral & Northeast

FACW - Facultative wetland


Western Jacob’s ladder is an erect, perennial, up to 40 tall forb that rises on a single stem from the upturned end of a short, slender, unbranched, horizontal, underground stem (rhizome).

The leaves are alternate. Lower leaves are pinnately divided into up to 27 narrow leaflets. The leaflets are lance-shaped, to 1½ long, and stalkless or almost stalkless. The margins are untoothed. The leaves get smaller and less divided as they ascend the stem. The leaf subtending the flowering stalk has 9 to 13 leaflets.

The inflorescence is a crowded, elongated, somewhat cylinder-shaped or egg-shaped, branched array (panicle) of several small clusters of flowers.

The flowers are bell-shaped and to long and wide. They are on 3 16 to ¼ long stalks, the stalks at least as long as the sepals. There are 5 sepals, 5 petals, 5 stamens, and 1 style. The sepals are green and form a bell-shaped structure (calyx) that is longer than the stalk of the flower. The petals are mostly blue but white at the base. They are joined at the base into a corolla tube then separated at the tip into 5 broadly triangular, widely spreading lobes that are longer than the tube. The stamens are as long as, or a little shorter than, the corolla. The anthers are white. The style is conspicuously longer than the stamens.

The fruit is a egg-shaped to round, 3-chambered, to long capsule with 1 to 10 seeds per chamber.




Up to 40 tall


Flower Color




Similar Species

  Charity (Polemonium caeruleum) is a garden plant that sometimes escapes cultivation. The leaf subtending the flowering stalk has only 3 to 7 leaflets. The corolla is purple to flesh-pink, not blue. The capsule is larger, ¼ to 5 16 long.  

Wet. Openings in conifer swamps with a blanket of sphagnum and other mosses and dominated by northern white cedar and sometimes tamarack and/or black spruce. Full or partial sun.




Late June to July




Distribution Map



2, 3, 4, 5, 24, 28, 30.

There are only six known populations of this plant, two in Wisconsin and four in Minnesota. All of the Minnesota sightings were in conifer swamps that been selectively logged. Three of the Minnesota populations are within 50 miles of each other in St. Louis County. One of those was found in 1944 but has never been found again. The fourth is in a conifer swamp in southeastern Itasca county.

The dark green counties on the map at left include locations verified by the Minnesota DNR and/or the Bell Herbarium. The light green county indicates one location in Clay County listed by BONAP. iNaturalist lists a sighting at the Minnesota Landscape Arboretum in Carver County. Arboretum sightings are not included on distribution maps.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (dicots)  
  Superorder Asteranae  


Ericales (heathers, balsams, primroses, and allies)  


Polemoniaceae (phlox)  
  Subfamily Polemonioideae  


Polemonium (Jacob’s ladder)  

Subordinate Taxa



  Polemonium occidentale var. lacustre  

Common Names


western Jacob’s ladder

western Jacob’s-ladder

western polemonium












A collective name for all of the petals of a flower.



A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.



Having the leaflets of a compound leaf arranged on opposite sides of a common stalk.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.























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Katy Chayka
  western Jacob’s ladder    
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Location: Itasca County

western Jacob’s ladder

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