Three-lobed Evening Primrose
oenothera triloba
Also known as: ["Three-lobed Sundrops","Three-lobed Moonflower"]
Overview
A herbaceous perennial native to North America, known for its distinctive three-lobed leaves and bright yellow flowers that open in the evening.
Benefits & Perks
["fragrant flowers","wildlife attractant (bees, butterflies, birds)","drought tolerant","low maintenance"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Myrtales |
| Family: | Onagraceae |
| Genus: | Oenothera |
| Botanical Name: | Oenothera triloba |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: rock gardens, sunny borders, or containers in full sun
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"10–35°C"}
- Hardiness: {"zones":"8–11"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent root rot.
- Soil Type: Well-draining, sandy, or loamy soil with some organic matter.
Maintenance Level
- Maintenance Level: low
- Toughness Level: moderate
- Pruning Frequency: Light pruning can be done every 4–6 weeks during the growing season. Major pruning is not usually needed.
- Pruning Intensity: Light to moderate. Remove only dead, damaged, or spent flower stems.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily). Tolerates partial shade but may produce fewer blooms.
Sunlight Tolerance Tips:
Acclimate plants gradually if moving from shade to full sun. Protect from intense midday sun in hot climates. Ensure good air circulation to prevent fungal issues in humid conditions.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun
Full sun is essential for blooming; rotate pots for even growth; avoid deep shade.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but infrequently; ensure soil dries between waterings; avoid overwatering to prevent root rot.
Soil
well-draining, sandy or loamy soil
pH: Slightly acidic to neutral (pH 6.0–7.0).
Ensure excellent drainage; avoid waterlogged soil; amend with organic matter for fertility.
Temperature
Prefers warm temperatures (65–85°F or 18–29°C). Tolerates mild frosts but thrives in mild to warm climates.
Protect from frost; ensure good air circulation in heat; adjust watering with temperature changes.
Fertilizing
every 4–6 weeks during growing season, none in winter
Fertilize sparingly to avoid leggy growth; stop fertilizing in late fall; apply after watering to prevent root burn.
Propagation
Methods
Stem cuttings or seed. Stem cuttings are faster and more reliable.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in moist medium.
- Maintain humidity.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (70–75°F or 21–24°C), humid, and bright but indirect light. Protect from direct sun.
Medium
Well-draining mix of perlite and peat moss or cactus potting mix.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots typically form in 2–4 weeks; plants may be ready to transplant in 8–12 weeks.
Tools Needed
Pruning shears, rooting hormone, small pots, well-draining medium, plastic wrap or propagator.
Quick Tips
Use healthy, non-flowering stems; keep medium consistently moist; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Pinch back tips to encourage branching; deadhead spent flowers by cutting just above a leaf node.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove spent flowers to prolong blooming.
Tools
Clean, sharp pruning shears or scissors.
Checklist
Use clean tools; prune in early morning; remove dead/damaged parts; deadhead spent flowers.
Repotting Guide
Best Season
Spring, before the active growing season begins.
Pot Size
Increase pot size by 1–2 inches in diameter.
Method
Gently remove the plant; trim any circling roots; place in a slightly larger pot with fresh, well-draining soil; water thoroughly after repotting.
Suggestions
Repot every 2–3 years or when the plant becomes root-bound. Young plants may need repotting annually.
Checklist
Choose a clean pot; use fresh soil; trim roots if needed; water after repotting; place in shade for a few days.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure drainage; avoid wetting leaves.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone. Water early in the morning to minimize evaporation and fungal issues. Allow excess water to drain away completely.
Watering Schedule Tips
Water deeply once every 7–10 days during active growth, reducing frequency to every 2–3 weeks in winter. Adjust based on rainfall and soil dryness.
Soil Improvement
Add perlite, coarse sand, or compost to improve drainage and aeration. Avoid heavy clay soils.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis or wilting in extreme heat; stunted growth or bud drop in cold stress.
Cold Stress
Low temperatures slow growth and may cause leaf discoloration or dieback. Prolonged cold can be fatal.
Solution: Provide frost protection in cold climates; move potted plants indoors during freezes; use mulch to insulate roots.
Hot Stress
Excessive heat can lead to wilting, leaf scorch, or reduced flowering.
Solution: Provide afternoon shade in intense heat; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during active growth; avoid winter feeding.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength every 4–6 weeks during the growing season (spring to early fall). Avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicOenothera triloba is not considered toxic to cats. There are no known adverse effects or physiological impacts on felines when ingested.
⚡ Toxic If:
if eaten
Dogs
Non-toxicOenothera triloba is not considered toxic to dogs. There are no known adverse effects or physiological impacts on canines when ingested.
⚡ Toxic If:
if eaten
Humans
Non-toxicOenothera triloba, commonly known as the three-lobed evening primrose, is not considered toxic to humans. There are no known toxic effects or physiological impacts associated with this plant.
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Does Oenothera triloba require full sun?
A: Yes, it thrives in full sun but can tolerate partial shade.
Q: How often should I water Oenothera triloba?
A: Water sparingly, as it is drought-tolerant and prefers well-drained soil.
Q: Are the flowers fragrant?
A: Yes, the bright yellow flowers are fragrant and open in the evening.
Quick Reference
| Family: | Onagraceae |
| Care: | easy |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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