Tufted Evening Primrose
Oenothera caespitosa
- Native to:
- Canada, Mexico, United States
Mary Vaux Walcott (en.wikipedia.org)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Onagraceae
- Genus:
- Oenothera
- Species:
- Oenothera caespitosa
- USDA Symbol:
- OECA10
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb , Subshrub
- Height:
- 30 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- High
- Bloom Months:
- may,jun,jul,aug
- Bloom Colors:
- white, pink
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★☆☆☆ Butterfly & moth species supported by this genus (NWF)
- Pollen Specialist Bee Keystone:
- ★★★☆☆ Native pollen specialist bee species supported by this genus (NWF)
Reported Fauna Sightings
Moths:White-lined sphinx moth (Hyles lineata)
Garden & Ecology Notes
- Wildlife Value:
- moths, bees
- Deer Resistant:
- Yes
- Fragrant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts from taproot following fire; found in fire-prone grassland and shrubland communities.
Soil Requirements
- Soil Type:
- gritty, well-drained, rocky soil
- pH:
- 6.0 - 8.0 (neutral to slightly alkaline)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- thrives in poor, low-nutrient soils
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–90 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate best with light exposure. Cold stratification improves germination rates.
The above propagation data sourced from Claude AI
Pre-treatment: 5 month outdoor cold moist stratification
Establishment: Seeds are hand collected in late August when capsules turn dark brown and woody. Seeds are black at maturity. Capsules are collected using pruning shears and are stored in paper bags prior to cleaning.
Source: npn.rngr.net
ORGHPS Germination Guide: Sow @ 20C. Germinates within 3 months.