Pink Evening Primrose (Oenothera speciosa Nutt.)
Also known as pinkladies, showy evening primrose, Mexican primrose, buttercups.
↑Summary
A small perennial with a disproportionately large pink flower, native to the south-central US but planted and established in the wild far beyond its native range.
↑Range - Expand
| Legend | Color |
| Native | |
| Expanded | |
| Native or Not Present | |
| Native or Expanded | |
| Expanded or Not Present | |
| Native or Expanded or Not Present |
This tentative map is based on our own research. It may have limited data on Canada and/or Mexico, and there is some subjectivity in our assignment of plants as introduced vs. expanded. Read more in this blog post.
This species is widely cultivated in gardens, but is also fairly weedy and aggressive, and readily colonizes anthropogenic habitats in urban and rural areas alike, including roadsides, railroads, fallow fields, and waste areas. A combination of garden introductions and spreading on its own into new habitats has led this plant to hugely expand its range east and northeast, and expand somewhat northwest as well. We mark all of this new range expanded because it is largely connected and contiguous with the native range.
↑Habitat
The pink evening primrose is found primarily in dry, sunny areas. Natural habitats include grasslands, savannas, and sunny gaps in open woodlands. Frequently more common in anthropogenic habitats including railroads, roadsides, pastures, and lawns.
Usually found on nutrient-poor soil with some gravel or rocky material, but can also occur on loam, sandy soil, and sometimes clay soils. It prefers disturbed sites, and especially in the humid east, it tends to be limited to dry sites and sites with a full sun exposure.
It grows equally well on steep slopes and flat terrain.
↑Life Cycle
This species is a rhizomatous perennial that often forms colonies.
Foliage is opportunistically evergreen or deciduous. The foliage often dies down in summer in response to drought, and the plant resprouts in fall. This pattern is an adaptation to the bimodal precipitation pattern, with wetter spring and fall and drier summers, that exists in much of its range, but a similar pattern can occur to a lesser degree even in areas with a unimodal precipitation peak, due to hotter and sunnier conditions in summer.
In the colder parts of its range, foliage can die down in response to winter cold. The combination of these two dormancies can lead this species to range from being green year-round, to having only a summer dormancy in some areas, and only a winter dormancy in others, and having two dormancies in others, sometimes with the exact pattern varying from year-to-year.
Plants growing in shade can sometimes persist if partly shaded out by taller vegetation such as trees or shrubs, but will rarely flower. This species can coexist with taller warm-season vegetation that emerges late, in regions where it goes dormant during summer months, such as in the more southerly portions of the tallgrass and mixed-grass prairie.
We could not find accurate information about this plant's lifespan; some sources claim a lifespan of only 2-3 years, but a lifespan this short seems unlikely, at least on suitable sites, given this plant's rhizomatous nature and formation of large clonal colonies. Mortality can occur if plants are overtopped by other species. This species likely persists on a site as long as high-light conditions reaching the ground persist, but it will quickly be out-competed by taller vegetation in the absence of disturbance.
↑Faunal Associations
The flowers attract a range of pollinators. The exact pollinator relationships of the flowers are not known. Small bees collect pollen but probably do not pollinate these flowers. The dimension of flower parts and fact that they open during the day (contrasting with many other Oenothera species) suggests that pollination happens primarily through hummingbirds, large butterflies, or day-active hawk moths.
↑Links & External Resources
• Oenothera speciosa (Showy Evening Primrose) | Illinois Wildflowers (About This Site)
• Oenothera speciosa (pink evening primrose) | USDA PLANTS Database (About This Site)
• Pinkladies | iNaturalist (About This Site)
• Oenothera speciosa (White Evening Primrose) | Missouri Botanical Garden Plant Finder (About This Site)
• Oenothera speciosa | CABI Invasive Species Compendium (About This Site)
• Oenothera speciosa | Biota of North America Project (BONAP) (About This Site)
• Oenothera speciosa | NatureServe Explorer (About This Site)
• Oenothera speciosa | Flora of North America (About This Site)
• Oenothera speciosa | Missouri Plants (About This Site)
• Oenothera speciosa Nutt. | Plants of the World Online (POWO) (About This Site)
