| Scientific Name: | Oenothera biennis |
| Common Name: | evening primrose |
| Family Name: | Onagraceae |
| Origin: | Canada - eastern, U.S. - northeast |
| Hardiness Zone: | Zone 4: (-34 to -29 °C) |
| Plant Type: | Biennial, Invasive plant |
| Mature Size: | 0.7 - 1.3m x 0.6 - 1.0m (height x width) |
| Habit: | Upright |
| Form: | Oval - vertical |
| Texture: | Medium |
| Landscape Uses: | Wildlife food |
| Exposure: | Full sun |
| Soil or Media: | |
| Leaves: | Simple, Alternate, Basal, Soft flexible, Pinnate venation, Pubescent, Lanceolate, Oblong, Dentate, Undulate (wavy) |
| Flowers: | Raceme, Yellow, Jun-Jul-Aug-Sep |
| Fruit: | Capsule, Brown, Jun-Jul-Aug-Sep |
| Key ID Features: | |
| Leaves in first year basal, lance-shaped, shallow-toothed; about 10-20cm long x 5cm wide; leaves in the second year spirally arranged on stem arising from the rosette; florets with four yellow petals, in terminal panicles, and open at dusk; capsules pod-like and contain >100 seeds. | |