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Yellow Evening Primrose (Oenothera serrulata)

Life history

Species overview

Yellow Evening Primrose (Oenothera serrulata), a Wisconsin Special Concern plant, is found mostly on steep bluff prairies along the Mississippi and lower St. Croix Rivers, as well as cedar glades and, occasionally, in moist prairies. Blooming occurs late June through early September; fruiting occurs early July through early October. The optimal identification period for this species is late June through early October.

Synonyms: Calylophus australis, Calylophus serrulatus, Meriolix intermedia, Meriolix oblanceolata, Meriolix serrulata, Oenothera serrulata var. typica


  • Distinguishing characteristics: Yellow 4-parted flower with floral tube 4-angled, funnel shaped, half as long as the ovary, covered in small hairs; fruit 4-angled; stigma broad and shield-shaped (not having 4 linear lobes as in Onethera spp.); leaves narrow (7 mm wide or less) with remote, sharp teeth.
  • Flower characteristics: Flowers yellow, 4-parted and only open in the morning; petals 5 to 12 mm long, floral tube 4-angled, funnel shaped, half as long as the ovary, and covered in small hairs; stigma broad and shield-shaped.
  • Fruit characteristics: Linear, roundly 4-angled, 1.5-3 cm long fruits develop and are covered with white or gray hairs.
  • Leaf characteristics: Alternate, simple, numerous, oblong to linear to inversely lance-shaped, 2 to 6 cm long x 7 mm wiide leaves with very small, remote, sharp teeth.


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


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Juniperus virginiana, Andropogon scoparius, Aster spp., Helianthus spp., Solidago rigida, Stipa spartea, Potentilla arguta.

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 Yellow Evening Primrose (Oenothera serrulata). 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 Oenothera serrulata in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2
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 mostly on steep bluff prairies along the Mississippi and lower St. Croix Rivers, as well as cedar glades and, occasionally, in moist prairies.
  • Soils:

Natural communities

This table lists the natural communities that are associated with Yellow Evening Primrose. 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
Dry Prairie 3
Sand Prairie 3
Eastern Red-cedar Thicket 2

Ecological landscapes

This table lists the ecological landscape association scores for Yellow Evening Primrose. 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 locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.
  • 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 and restore open habitat through selective clearing and brushing.
  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).


Yellow Evening Primrose Photo.

Photo © Emmet Judziewicz.

Yellow Evening Primrose Photo.

Photo © Dan Carter.

Yellow Evening Primrose Photo.

Photo © Corey Raimond.

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