Virginia ecotype
Duration: Biennial
Habit: Upright, branching, naturalizing
Size: Up to 8 ft. tall, half as wide
Flowering time: Jun, Jul, Aug, Sep, Oct
Bloom color: Yellow
Habitat: Ditches, roadsides, fieldsMoisture: Dry to average, well draining
Light: Full sun, part sunSoils: Clay, loamy, sandy, rocky
Uses: Wild meadows, pollinator and hummingbird gardens, screening, early succession planting
Oenothera biennis (Evening primrose)
Common evening primrose is an upright biennial rising on a single or branched stem from a fleshy taproot. Biennials are plants that germinate year one and flower the next season.
Oenothera biennis can grow up to 8 feet tall, though usually shorter, especially in poorer soils. In the first year it forms a tight rosette of basal leaves. Second year it sends up a flowering stem tipped with yellow, fragrant flowers. It dies after bearing its numerous pods with pepper-like seeds.
A common misconception is that this plant spreads via underground rhizomes, but it is instead a prolific self-seeder. It does well in newly established landscapes, but does not persist with the increase of higher plant competition, making it an early successional species.
The seeds of Oenothera biennis can stay in the soil for many decades, up to 70 years, waiting to germinate when soil is disturbed and they are exposed to light which is needed to sprout. As such it is common in disturbed sites.
The yellow blooms are pollinated by native bees, butterflies, moths and hummingbirds. Several rare pollen specialist bees visit Oenothera genus flowers, making this species one of very, very few available plants that these bees rely upon to survive. The seed is a great food source for goldfinches and mourning doves. It is a larval host plant for several moths. Insects overwinter in their strong stems.