PlantFiles: Common Evening Primrose, Night Willow-herb, Hoary Evening Primrose
Oenothera biennis

I grew this plant as part of a wildflower mixture. It kept getting taller and taller, and looking more like a weed. Finally, at about 5 ft tall, it began to bloom. The flowers themselves are nice, but the size of the plant overwhelms them and leaves much to be desired. Mine did not reseed, and I don't consider it much of a loss.

Moths pollinate the flowers, particularly Sphinx moths. Other occasional visitors include the Ruby-Throated Hummingbird, honeybees, bumblebees, and Anthedonia compta (Primrose Miner Bee), the latter being an oligolege. These insects seek nectar, although some of the bees collect pollen. The caterpillars of several moths feed on the foliage. This includes Endryas unio (Pearly Wood Nymph), Desmia funeralis (Grape Leaffolder Moth), Hyles lineata (White-Lined Sphinx), and Mompha eloisella (Momphid Moth; bores through stems). Various beetles feed on the foliage, including Popillia japonica (Japanese Beetle), Grahops pubescens (Leaf Beetle sp.), Altica fusconenea (Flea Beetle sp.), and several Curculio beetles. The seeds are eaten by goldfinches.

Grows here in Zone 3. Self-seeds abundantly here in Zone 3. I have a garden filled with them started from one single plant. I would rate it as quite invasive.

I purchased a pack of mixed wild flowers and some of these came up last year. During the winter here in Texas, which is mild, but it does get cold, the green leaves part of the plant stayed alive all winter long being low to the ground. WIth the onset of spring this year they shot up to about 3-4 feet tall and produced a lot of flowers all summer. They were under a shade tree and received partial shade and some sun. You do have to watch for the aphids, they seem to love this plant. You can contol them with a soapy water mixture sprayed on the plant.

This plant grows in the Dunes at the beach. It seems to do very well there and is doing a part in keeping the sand from blowing where it's pretty thick. It dosen't seem to be effected by the salt water or spray. Some of it is pretty close to the surf and it has been growing there for quite some time and it is flowering and sending out more runners..

Evening primrose is a biennial plant with numerous, crinkled, lance-shaped leaves and green stems with red splotches. The flowers on this plant were found blooming on a cloudy day, but commonly only bloom early morning or evening. Flowers are bright yellow, fragrant with four broad petals. This plant was found growing alongside a country road and stands about 7 feet tall. Flowers are produced all along the stalk and bloom is continuous from June through autumn.

Evening primrose was used by the North American Indians for a variety of medical problems. This plant is grown commercially for its seed oil which is rich in GLA (gamma linoleic acid) fatty acids; cis-linoleic (70%), cis-gammalinolenic acid (9%).

Above ground parts are thought to have astringent properties, used to treat whooping cough, digestive problems, asthma etc; oil has been applied externally to treat itchy skin conditions, internally to lower blood pressure, prevent clumping of the platelets, premenstrual problems. Dangerous to take if suffering from epilepsy.

Most of my information was taken from the Ontario Ministry of Agriculter and Food