Common Eveningprimrose

Oenothera biennis

Weed Description
Usually a biennial or a winter annual, but may rarely occur as a summer annual. Common eveningprimrose has narrow leaves with untoothed margins and produces many showy yellow flowers. This weed is primarily a weed of landscapes, nurseries, some agronomic crops, and occasionally turfgrass and lawns. Common eveningprimrose occurs throughout the southern and eastern United States.

Seedlings
Cotyledons are 6 to 11 mm long, and usually egg-shaped with a short petiole. The stem at the base of the cotyledons has a reddish tint. Leaves initially develop as a basal rosette. Upper leaf surfaces of young leaves may have a few hairs near the base.

Leaves
Leaves are elliptic to lanceolate in outline, are relatively narrow, and have untoothed margins. Leaves have a distinctive white or pink midvein and may have wavy margins. Leaves along the erect flowering stem are alternate and become progressively smaller up the stem.

Stems
Erect, reaching as much as 6 1/2 feet in height.

Flowers
Occur in the upper leaf axils and are without flower stems (sessile). Flowers consist of 4 bright yellow petals (12 to 25 mm long). Individual flowers are approximately 3/4 to 2 inches wide.

Fruit
An erect, hairy capsule that is approximately 1/2 to 1 1/2 inches long. Many seed are arranged in rows within the capsule.

Roots
A taproot.

Identifying Characteristics
Erect plants with lanceolate or elliptic leaves that have untoothed margins, and showy yellow flowers. Common eveningprimrose is very similar in appearance to Cutleaf Eveningprimrose (Oenothera laciniata), but cutleaf eveningprimrose has toothed margins and usually grows much more prostrate than common eveningprimrose.

Trouble identifying a weed?

For additional assistance identifying weeds, contact Dr. Kevin Braldly, State Extension Weed Scientist (bradleyke@missouri.edu).

Office of Programs

University of Missouri

Common Eveningprimrose

Oenothera biennis

Trouble identifying a weed?