A native of southern and central US, Missouri primrose is also called Ozark sundrops. It is a herbaceous perennial and member of the willowherb familiy, Onagraceae, that also includes Fushia, Clarkia, and Gaura. Plants grow 6-12″ tall and have narrow, lance-shaped leaves that are 1-4″ long. In summer, fragrant, lemon yellow flowers appear that are 3-5″ wide and have paper thin petals that give them a delicate look in spite of their large size. They are borne singly on reddish stems that tend to sprawl, and open in the afternoon from large, reddish buds. Each flower lasts for several days and is followed by a winged persistent seed pod. In the South blooming may stop when the temperatures rise. The genus name, Oenothera, comes from the Greek words oinos meaning wine and theras meaning booty, and refers to the use of the root of some plants in the genus for scenting wine. The specific epithet, macrocarpa, comes from the Greek macro- meaning large, and karpos meaning fruit.
Type: Herbaceous perennial.
Bloom: Lemon yellow, 3-5” fragrant flowers from all summer while temperatures are cool.
Foliage: 2-4” lance shaped light-green leaves.
Size: 6-12” H x 1-1 ½” W.
Light: Full sun; tolerates some shade.
Soil: Fertile, deep, well-drained but tolerates less as long as soil is well-drained.
Hardiness: Zones 3-7.
Care: In North, mulch in winter.
Pests and Diseases: None of importance but roots will rot in poorly drained soil.
Propagation: Seed or division after flowering.
Companions: Coreopsis ‘Moonbeam’, Catmints (Nepeta spp), irises.
Outstanding Selections: ‘Greencourt Lemon’ (2-2 ½” flowers).