Evening Primrose
oenothera biennis
Also known as: ["Common Evening Primrose","King's Cure-all","German Rampion"]
Overview
A biennial herb native to North America, known for its fragrant yellow flowers that bloom in the evening.
Benefits & Perks
["fragrant flowers","wildlife attractant (bees, butterflies, birds)","drought tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Myrtales |
| Family: | Onagraceae |
| Genus: | Oenothera |
| Botanical Name: | Oenothera biennis |
Plant Characteristics
Basic Information
- Category: Herbs & Weeds
- Suitable Location: outdoor garden bed in open, sunny area
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–35°C"}
- Hardiness: {"zones":"3–9"}
- Misting: rarely required, only if grown in very dry indoor conditions
- Drainage: Fast-draining to prevent root rot.
- Soil Type: Well-draining, loamy soil with some organic matter. Tolerates poor soils but thrives with moderate fertility.
Maintenance Level
- Maintenance Level: low
- Toughness Level: high
- Pruning Frequency: As needed throughout the growing season, especially after flowering.
- Pruning Intensity: Light pruning; remove only dead or spent parts.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily). Tolerates partial shade but may produce fewer flowers.
Sunlight Tolerance Tips:
Acclimate seedlings gradually to full sun to prevent scorching. In hot climates, provide some afternoon shade to protect from intense heat. Indoors, place near a south-facing window.
Care Requirements
Care Difficulty
easyeasy
Sunlight
full sun
Rotate plants for even light exposure; use reflective surfaces to boost light; monitor for signs of sunburn or etiolation.
Watering
every 7–10 days during active growth, less frequently in dormant periods
Water thoroughly but infrequently to encourage deep roots; allow soil to dry between waterings; avoid overhead watering to prevent fungal issues.
Soil
well-drained, sandy loam with moderate fertility
pH: Slightly acidic to neutral (pH 6.0–7.0).
Avoid heavy clay soils; ensure good aeration; mulch to retain moisture and suppress weeds.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C). Tolerates cold but may struggle in extreme heat.
Avoid sudden temperature fluctuations; protect from frost; maintain consistent day/night cycles.
Fertilizing
every 4–6 weeks during growing season with balanced liquid fertilizer
Apply fertilizer to moist soil to prevent root burn; stop feeding during dormancy; use organic options like compost tea for gentle nutrition.
Propagation
Methods
Seed propagation is the most common method. Stem cuttings can also be used but are less reliable.
Step-by-Step Propagation Guide
- For seeds: sow shallowly, keep moist, and thin seedlings. For cuttings: take a 4–6 inch cutting, remove lower leaves, dip in hormone (optional), plant in medium, and maintain humidity.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (70–75°F or 21–24°C), high humidity, and bright indirect light for cuttings. Seeds need consistent moisture and warmth.
Medium
Well-draining seed starting mix or a blend of peat and perlite.
Hormone
Not typically required for seeds; rooting hormone may help with stem cuttings.
Timeline
Seeds germinate in 1–3 weeks under optimal conditions. Stem cuttings root in 2–4 weeks.
Tools Needed
Pruning shears, rooting hormone (optional), seed trays, misting bottle, heat mat (optional).
Quick Tips
Use fresh seeds for best germination; provide bottom heat for seeds; maintain humidity for cuttings.
Pruning & Repotting
Pruning Guide
Method
Snip off dead stems at the base and deadhead spent flowers to promote reblooming.
Pruning Plan
Minimal pruning is needed. Focus on removing dead or damaged stems and spent flowers to encourage continuous blooming.
Tools
Hand pruners or sharp scissors.
Checklist
Sterilize tools; prune dead or damaged growth; deadhead spent flowers; avoid over-pruning.
Repotting Guide
Best Season
Early spring before new growth begins.
Pot Size
One size up from the current pot (e.g., +2 inches in diameter).
Method
Gently remove the plant, trim any circling roots, place in a slightly larger pot with fresh soil, and water thoroughly.
Suggestions
Not typically required for outdoor plants. Potted plants may need repotting every 2–3 years if root-bound.
Checklist
Choose the right pot size; use fresh soil mix; handle roots carefully; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply at the base; ensure proper drainage; adjust frequency seasonally.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone. Apply until water drains from the bottom, then stop to prevent waterlogging. Water in the morning to minimize evaporation and fungal growth.
Watering Schedule Tips
Water deeply once per week during active growth, reducing frequency in winter to every 2–3 weeks. Adjust based on rainfall and soil moisture retention.
Soil Improvement
Add compost or well-rotted manure to enhance fertility and structure. Incorporate sand or perlite for better drainage.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis or wilting in excessive heat; stunted growth or bud drop in cold stress.
Cold Stress
Low temperatures slow growth and may cause leaf discoloration or dieback, especially in young plants.
Solution: Provide a layer of mulch to insulate roots; move potted plants to a sheltered location; avoid overwatering in cold conditions.
Hot Stress
Excessive heat can lead to wilting, flower abortion, and reduced vigor, especially in humid conditions.
Solution: Water deeply in the morning; provide afternoon shade; increase air circulation; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during active growth; avoid winter feeding; monitor for nutrient burn.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength every 4–6 weeks during the growing season. Avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicOenothera biennis is generally non-toxic to cats. However, ingestion of large quantities of the seeds may cause mild gastrointestinal distress due to the plant's fatty acid content. The plant is not typically considered harmful to felines.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten in large quantities
Dogs
Non-toxicOenothera biennis is generally non-toxic to dogs. However, ingestion of large quantities of the seeds may lead to mild gastrointestinal upset due to the plant's fatty acid content. The plant is not typically considered harmful to canines.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten in large quantities
Humans
Non-toxicOenothera biennis, commonly known as evening primrose, is generally considered non-toxic to humans. However, ingestion of large quantities of its seeds may cause mild gastrointestinal discomfort due to the presence of certain fatty acids and compounds. The plant is widely used in traditional medicine for its omega-6 fatty acids and other beneficial compounds.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten in large quantities
Frequently Asked Questions
Q: Is Evening Primrose edible?
A: Yes, the leaves, roots, and seeds of Evening Primrose are edible and have been used in traditional cuisine.
Q: Does Evening Primrose attract pollinators?
A: Yes, its fragrant flowers attract bees, butterflies, and other pollinators.
Q: How long does Evening Primrose bloom?
A: Evening Primrose typically blooms from mid-summer to early fall, with flowers opening in the evening and lasting for one day.
Quick Reference
| Family: | Onagraceae |
| Care: | easy |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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