Oenothera - Wikipedia
- An account of the genus Oenothera, with advice on cultivation and a list of the better known species.
- http://en.wikipedia.org/wiki/Evening_primrose

Oenothera
- Photographs, descriptions and advice on growing several species of evening primrose, from Desert Tropicals.
- http://www.desert-tropicals.com/Plants/Onagraceae/Oenothera.html

Evening Primrose
- An account of Oenothera macrocarpa, a wild flower from the Great Plains region of the USA which is also an attractive garden plant.
- http://www.gpnc.org/evening.htm

Evening Primroses in the Garden
- The cultivation of Oenothers species, with photographs and descriptions of the most desirable, by the holder of the National Plant Collection of Oenothera.
- http://nccpg.com/oenothera/