FRAGRANT EVENING PRIMROSE

Oenothera caespitosa

This memorable plant is very widely distributed in the Intermountain region and also in the desert Southwest and the western Great Plains. As its name suggests, it opens its strongly-perfumed flowers in the evening, when the sphinx moths that are its main pollinators are most active. It is a common sight along gravelly road shoulders in the spring, especially noticeable in the early morning hours when its very large, white blossoms are still open. These wither and fade to pink by midday, but the next night, another set of blossoms will open. The plant can keep up this extraordinary nightly display for several weeks, and one or two extra waterings in midsummer can extend this period even further. Fragrant evening primrose in the wild is usually not a very large plant, but in more fertile soils or somewhat wetter climatic regimes, the plants sometimes approach bushel-basket size and support truly prodigious floral displays. This plant often grows with Utah ladyfinger milkvetch in nature and the two plants look very pretty planted together.