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Wildflowers!
by Jane Scully

Evening Primrose
(Oenothera biennis)

This 4-petaled yellow beauty of summer is a fascinating example of the many faces within various plant families. Blooming only from dusk to noon the next day, individual flowers blossom in the branched cluster at the end of the hairy, often purple-tinged stem with slightly toothed leaves. During the day, the 2 to 5 foot plant looks unremarkable, with faded flowers among the buds that will then bloom later in the evening to a shining vivid yellow with a lemony scent that attracts the pink night-moth as a pollinator.

Contrast this with another member of the native evening primrose family, known as sundrops, that has the same bright-yellow flowers but blooms only in the daytime. It has the same 1 to 2 inch-wide flowers, 4 petals and similar height. Jekyll and Hyde? Yin and yang? You decide.

The cross-shaped flowers of the evening primrose arise from a long floral tube. The 8 stamens - the filaments or slender stalks that bear knob-like, pollen-bearing tips - are prominent. The plants' life cycle is expressed by its name, biennis, or biennial, with basal leaves becoming established the first year and flowering occurring the second. The seeds are important as bird seed.

Check out the many places you can find evening primrose in our parks by using our Nature Finder.

Interesting facts:

A fascinating and felicitous early work called How to Know the Flowers, by Mrs. William Starr Dana, first published in 1893, has charming descriptions of the evening primrose.

"One brief summer night exhausts the vitality of these delicate blossoms. The faded petals of the following day might serve as a text for a homily against all-night dissipation...."

This is my first find of a plant used by the American Indians for obesity. Recent research has demonstrated that extracts of this plant can alleviate imbalances and abnormalities of essential fatty acids in prostaglandin production. The seed oil may be useful in various eczemas and just about everything else, even alcoholism.