Common evening primrose
Oenothera biennis
Biennis
About this plant
Oenothera biennis, known as common evening primrose, is a biennial plant famous for its yellow flowers that open in the evening. It has tall stems and lance-shaped leaves. The plant is often grown for its attractive flowers and seeds, which are used to produce evening primrose oil with health benefits. It is also appreciated for its ability to attract pollinators like moths and bees.
Taxonomy
- Genus
- Oenothera
- Family
- Onagraceae
- Higher classification
- Order Myrtales
- Plant type
- Perennial
- Lifespan
- Biennial
Origin & Distribution
- Native region
- North America
- Distribution
- Native to North America, it is now widely grown in temperate regions around the world, including Europe and Asia.
Care
- Light preference
- Full sun
- Suitable locations
- Outdoor, Balcony, Greenhouse
- Preferred window facing
- South-facing, West-facing
- Watering frequency
- Moderate
- Watering interval
- 5–10 days
- Humidity
- Normal
- Minimum
- -30 °C
- Maximum
- 35 °C
- Optimal
- 15-25 °C
- USDA hardiness zones
- 4-9
- Soil pH
- 6.0-7.5 (neutral to slightly acidic)
- Soil type
- well-draining loam or sandy soil
Watering. Water moderately, allowing the soil to dry out between waterings. It tolerates drought once established but performs best with occasional watering during dry spells.
Fertilizing. Fertilize lightly in early spring with a balanced, all-purpose fertilizer. Avoid over-fertilizing as it can reduce flower production.
Oenothera biennis is a hardy plant that grows well in sunny spots and tolerates dry soil. It needs minimal care and is resistant to many common problems. Overwatering can cause root issues, so let the soil dry between waterings.
Propagation
- Propagation methods
- Seeds, Division
- Care difficulty
- Easy
Ornamental features
- Flowering
- Yes
- Flowering period
- summer
Bright yellow flowers that open in the evening, tall upright stems, and attractive seed pods.
Toxicity & Safety
- Toxic to humans
- Non-toxic
- Toxic to pets
- Non-toxic
- Weed potential
- Low spread
Non-toxic to humans and pets, safe to grow around children and animals.
Allergy information
- Allergy risk
- Low
- Allergy triggers
- Pollen
- Pollen level
- Low
Even though Oenothera biennis produces pollen, it is not a common cause of allergies. People sensitive to pollen might experience mild reactions during its flowering season. To reduce exposure, avoid close contact when the plant is blooming.
Common problems
Overwatering can lead to root rot. Poor flowering may occur if the plant is in too much shade. Occasionally, it can be affected by aphids or fungal diseases if air circulation is poor.
Uses
Grown mainly as an ornamental plant for its attractive flowers and as a source of evening primrose oil, which is used in herbal remedies. It also supports pollinators in the garden.
Notes
Prune dead flower stems after blooming to encourage healthy growth. It can self-seed readily, so remove seed pods if you want to control spreading. Suitable for wildflower gardens and naturalized areas.