This perennial member of the evening primrose family is a native wildflower found throughout Eastern United States and Canada, though it is less common in New York State and New England.

The flowers have four yellow petals with orange stamens and a pistil that divides at the end to form four long stigmas in the form of a cross. Each yellow flower is about two inches in diameter and is saucer or cup-shaped. Each individual flower is short-lived, but the plant produces new blooms in a terminal flat-topped cluster. These terminal clusters contain 3-10 flowers. Flowers are produced in succession over a period of two months. Unlike its close relative, the evening-primrose, the common sundrops blooms during the day.

The leaves are lance-shaped and are usually not toothed. The seedpod is a strongly ribbed capsule. The sundrops plant grows from one to three feet tall, generally in places with full exposure to the sun. The blooming period is May to August depending on location. The soft, hairy stem is often tinged with red.

It is popular as a cultivated plant in butterfly, border or rock gardens and is deer resistant. Cultivars are commercially sold. It can spread rapidly but is not aggressive. The sundrops also tolerates heat, drought and erosion.

It is also called the narrowleaf evening primrose, yellow sundrops or the Southern sundrops. The smaller sundrop (O. perennis) has smaller blossoms and flowers that bloom along the length of the stem.