Sundrop and evening primrose are the day and night bloomers of their genus, and the common name is a perfect choice for petals that look like molten gold. They are often found in old-time gardens. The genus is named for the Greek word oinos, "wine," and thera, "to hunt," because of confusion regarding this flower and another genus with roots possessing the aroma of wine.
Description of sundrop: Simple alternate leaves on strong stems grow up to 2 feet high. They are topped by clusters of bright yellow, 4-petaled flowers up to 2 inches across that bloom in the summer. Basal rosettes are evergreen in colder areas. Sundrop ease of care: Easy.
How to grow sundrop: Sundrops are extremely tolerant of poor soil and are very drought-resistant, but the ground must be well-drained and full sun is necessary. If given a spot in good soil, they become quite pushy, but are easily controlled since they are shallow-rooted.
Propagating sundrop: By division in spring or by seed.
Uses for sundrop: Sundrops are perfect for the wild garden and can hold their own at the edge of a field or meadow. Most of the flowers can be gathered for winter bouquets because the seedpods are very attractive.
Sundrop related species: There are a number of species useful for the garden. Oenothera fruticosa is a wildflower of the eastern United States, with 2-inch yellow flowers on 11/2- to 2-foot stems and is the type usually found in old gardens. 'Youngi' is offered by nurseries today. 'Fireworks,' with brilliant yellow flowers on 18-inch stems. Oenothera macrocarpa stays about 1 foot high, but the blossoms are often showy and 4 inches wide. The trailing stems carry a succession of lemon-yellow flowers opening in early afternoon. They are especially suited for the rock garden where the stems can tumble about and because their soil must never stay wet for any length of time. The seedpods are very attractive. Oenothera speciosa is another wildflower that is a rampant spreader in the wild garden; 'Rosea,' with light pink flowers 2 inches in diameter on high stems, is excellent for border edging. O. berlandieri is similar and a bit less aggressive. 'Siskiyou' is deep rose pink.
Scientific name for sundrop: Oenothera species