Missouri evening primrose (Oenothera macrocarpa) is our May Plant of the Month for 2025. This native groundcover type plant is one of the best for tough, rocky or dry soils. Native to Kansas, Nebraska, Missouri, Oklahoma, and Texas, it grows in a variety of landscape types, but is predominant in the Flint Hills and the Smoky Hills of Kansas and the prairies of western Missouri. It grows only 6 inches tall, but can spread outward up to 3 feet.
Evening primroses, which include around 80 species, 14 of which are native to the Central Great Plains region, the flowers open in the evening and remain open all night and into mid morning, before closing. Species can be annuals, perennials, or biennials. They are pollinated mainly by night-flying moths and other insects, and bees which come out in early morning. Most species bloom from May to October. The flowers are open for the night, and then close, and shrivel up, like a daylily.
Insect Associations
The Missouri evening primrose is known to be pollinated mainly by sphinx moths, which fly both at night and during the day. There are 11 pollen specialist bees which use evening primrose as their host, but are not strictly limited to Missouri evening primrose. The white-lined sphinx moth uses it as a host plant however, and is considered the primary pollinator.
Some leafcutter bees may also use the flowers for lining their nests, I have seen holes cut by them in the petals. There are also a few other moths, including primrose cochylid moth, the white-based mompha moth, and the red-streaked mompha moth.
Companion Plants
The Missouri evening primrose is a groundcover, or low mounding plant, so it needs to be put near the front of a bed, in full sunlight. However, there are still many plants which complement it, and can be planted nearby. Just remember that the companion plants need to have similar light and moisture requirements for best results.
- Rose verbena
- Liatris punctata
- Breadroot Scurfpea
- Purple poppy mallow
- Fremont’s Clematis
- Pasque flower
- Prairie smoke
- Dakota verbena
- Resinous skullcap
- Ground plum milkvetch
Conclusion
Missouri evening primrose is the perfect plant for the edge of dry stone wall or stone ledge in hot, full sun. It has few pest problems and provides early morning color and brightness all night long for night moths. Plant it in the moon garden for added effect.
Happy planting!
