Common eveningprimrose – Oenothera biennis

Eveningprimrose flower

Eveningprimrose flower

Eveningprimrose plant

Eveningprimrose plant

Eveningprimrose rosette

Eveningprimrose rosette

Common eveningprimrose

Oenothera biennis L.
Onagraceae (Eveningprimrose family)

Life cycle
Usually an erect biennial or winter annual. Occasionally a summer annual.

Leaves
Alternate, narrow oval-shaped, smooth to slightly wavy leaf margins, with distinctive pink to white midveins. Leaves initially develop from a basal rosette.

Stems
Erect, semiwoody, approaching 5 feet in height. Stem usually branches only at the top and may be visible through the winter.

Flowers and fruit
Flowers are yellow, attached to fused sepals forming a tube and found in terminal spikes. Seed capsules are woody, cylinder-shaped and thickest near the bottom.

Reproduction
Seeds.

Similar weeds
Cutleaf eveningprimrose (O. laciniata Hill)
Differs by having a prostrate to moderately erect, branching stem; wavy and coarsely toothed leaves; yellow to reddish flowers in the upper and middle leaf axils; and linear, cylinder-shaped seed capsules.