As a long-flowering plant, the Missouri evening primrose makes sparse locations with its lemon-yellow flowers shine all summer long. Here are tips for planting and care.
Scientific name: Oenothera macrocarpa
Plant family: evening primrose family (Onagraceae)
Other names: bigfruit evening primrose, Ozark sundrop
Sowing time: spring
Planting time: spring and autumn
Flowering period: June to September
Soil quality: stony to loamy, low in nutrients
These information are for temperate climate!
Use in: flowerbeds, individual position, group planting, dry stone walls, borders, natural garden, rock garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 5 (-26 °C / -15 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of Missouri evening primrose
Plant order, origin and occurrence of Missouri evening primrose
The Missouri evening primrose is a flowering perennial of the evening primrose family (Onagraceae), whose natural range extends from the southern USA to Mexico. With preference, it grows on sandy, open places and limestone rocks. When it was brought to England in 1811, it was named Oenothera missouriensis. Today, Oenothera macrocarpa – which translates as the bigfruit evening primrose – is the correct botanical name. It is a particularly attractive flowering species for rock gardens, gravel areas and dry stone walls.
Characteristics of Missouri evening primrose
The bigfruit evening primrose grows with its low-lying shoots to a bushy cluster. It reaches a height of 15 to 25 centimeters (6 to 10 in). Its large-shelled flowers are lifted above the leaf carpet by the upright flower stems. A deep-reaching taproot anchors them securely in loose soil.
The shoots of the Missouri evening primrose are densely covered with elongated-lanceolate leaves of fresh green color. The leaves are deciduous.
From mid-June to early September, the plant inspires with its continuously renewing lemon yellow flowers. The individual blossoms open their cupped petals only in the late afternoon hours and fade until the next morning. It exudes an intense fragrance, attracting moths to pollinate it.
Also, the inflated seeds of the plant are very decorative due to their red tinged center. Like all evening primroses, including the common evening primrose, the perennial plant forms capsule fruits.
Missouri evening primrose – cultivation and care
Bigfruit evening primrose needs a full sunny and dry-warm place.
A lean, well-drained soil is best suited for the cultivation of the bigfruit evening primrose.
Planting Missouri evening primrose
When planting the Missouri Evening Primrose, one should ensure good soil drainage with a thick layer of gravel or sand. A planting distance of 45 centimeters (18 in) is recommended; if used in a large area, plant four specimens per square meter. Ideal planting times are spring and autumn.
Care / Watering / Fertilization
Freshly planted young plants of the Missouri evening primrose should be covered with brushwood over the winter to protect them from moisture and cold. To prolong the flowering time, one plucks off withered plants regularly.
Because of its long taproot, a division of the Missouri Evening Primrose is not possible.
Oenothera macrocarpa only produces seeds when a second plant is nearby. Then it usually ensures its survival by self-sowing. But you can also sow seeds in spring, or you can cut cuttings and let them root in the soil.
Diseases and pests
The bigfruit evening primrose shows a certain susceptibility to powdery mildew. If root rot occurs, the cause is usually moisture.
Missouri evening primrose is quite hardy down to -26 °C / -15 °F. It should be covered with brushwood over the winter to protect it from moisture and cold.
Use in the garden
Harmoniously looks a planting of the bigfruit evening primrose in rock garden plants, on gravel surfaces, rock steppes or in cracks and crowns of dry walls. Pretty partners are low Canterbury bells, grayish catnip, stonecrop and speedwell. As in natural habitats, they can also be combined quite exotically with prickly pear cactus and Mexican feathergrass.
There are two grey-silver-leaved selections of subspecies of the pure species, which visually harmonize better with stony, rocky habitats than the pure species with its striking fresh green leaves:
- Oenothera macrocarpa ssp. incana ‘Silver Blade’ is particularly large-flowered and has silvery foliage.
- Oenothera macrocarpa ssp. fremontii ‘Silver Wings’ forms fine silvery and wavy leaves.