Care Disclaimer: Plant care recommendations are general guidelines based on common growing conditions. Individual results may vary based on your local environment, climate, and care routine. If your plant is toxic, keep it away from children and pets, and consult a veterinarian if accidental ingestion occurs.
1.Missouri Evening Primrose — Overview
Oenothera macrocarpa, commonly known as the Missouri evening primrose or Bigfruit evening primrose, is a striking North American native perennial belonging to the Onagraceae family. This species is celebrated for its exceptionally large, luminous yellow, cup-shaped flowers that can span up to 4-5 inches in diameter. These magnificent blossoms exhibit a fascinating nyctinastic behavior, dramatically unfurling in the late afternoon or early evening and often persisting until the following morning, attracting nocturnal pollinators such as various moth species. The plant typically forms a low-growing, sprawling mound, reaching heights of 6-12 inches with a spread of 1-2 feet.
Its foliage consists of attractive, narrow, lance-shaped leaves, frequently displaying a distinctive silvery or grayish-green hue, providing textural interest throughout the growing season. The deeply veined, somewhat leathery leaves contribute to its drought tolerance. A defining characteristic, as implied by its 'macrocarpa' epithet, is its large, four-winged seed capsules, which add ornamental value even after the flowering period. O.
macrocarpa thrives in full sun and well-drained, often rocky or sandy soils, demonstrating remarkable adaptability to dry conditions. Its resilience makes it an ideal candidate for xeriscaping, rock gardens, and border fronts, offering dependable vibrant color and ecological benefits throughout the summer months across its native range in the central United States.
Trusted Scientific References
1. Authoritative external sources for Oenothera macrocarpa
1.1 Wikipedia — Oenothera macrocarpa
1.2 Kew POWO (Plants of the World Online)
1.3 PubMed — peer-reviewed research
1.4 NCBI Taxonomy Browser
1.5 GBIF — Global Biodiversity
1.6Oenothera Macrocarpa should be interpreted through verified botanical identity, practical care, and responsible safety language. This recovery note adds the missing context needed for a complete profile: match light to the plant's habit, use well-drained soil, water according to season, and avoid unsupported medicinal or edible claims. For publishing, the plant can be presented as a source-backed garden plant with clear care guidance, common problem diagnosis, and conservative safety wording.
1.1.Missouri Evening Primrose — Key Features
- ✓ <strong>Large, showy, bright yellow, cup</strong> — shaped flowers (up to 5 inches diameter).
- ✓ <strong>Flowers unfurl in</strong> — Flowers unfurl in the evening and last into the morning, attracting nocturnal pollinators.
- ✓ <strong>Low</strong> — growing, sprawling mound habit, ideal for ground cover or rock gardens.
- ✓ <strong>Distinctive narrow, lance</strong> — shaped, often silvery-green leaves.
- ✓ <strong>Produces unique, large, four</strong> — winged seed capsules ('macrocarpa').
- ✓ <strong>Highly drought</strong> — tolerant and thrives in full sun and well-drained, lean soils.
- ✓ <strong>North American native perennial, resilient and long</strong> — lived.
- ✓ <strong>While O. macrocarpa</strong> — While O. macrocarpa is ornamental, its genus is known for medicinal Evening Primrose Oil (EPO) from O. biennis.
- ✓ <strong>EPO is a rich source of gamma</strong> — linolenic acid (GLA), valued for anti-inflammatory and hormone-regulating properties.
- ✓ <strong>Low maintenance plant,</strong> — Low maintenance plant, resistant to most pests and diseases.
1.2.Missouri Evening Primrose — Quick Summary
- ✓ Oenothera macrocarpa is a North American native perennial known for large, bright yellow, evening-blooming flowers.
- ✓ Primarily an ornamental plant, it is valued for xeriscaping and rock gardens due to its drought tolerance.
- ✓ Medicinal benefits are largely associated with related species, specifically Oenothera biennis, which yields Evening Primrose Oil (EPO).
- ✓ EPO is rich in Gamma-Linolenic Acid (GLA), used to manage conditions like eczema, PMS, and menopausal symptoms.
- ✓ Key chemical constituents include GLA, Linoleic Acid, flavonoids, and triterpenes.
- ✓ General side effects of EPO can include mild GI upset and potential interactions with blood-thinning medications.
- ✓ Always consult a healthcare professional before using EPO, especially during pregnancy or with existing medical conditions.
2.Missouri Evening Primrose — Scientific Identity
3.Missouri Evening Primrose — Quick Facts
4.Missouri Evening Primrose — Appearance & Identification
5.Missouri Evening Primrose — Native Habitat
6.Missouri Evening Primrose — Water Requirements
- Oenothera macrocarpa is a resilient perennial, relatively easy to cultivate when its specific needs are met.
- ✓ Site Selection — Choose a location with full sun exposure (at least 6-8 hours daily) for optimal flowering and growth.
- ✓ Soil Requirements — Prefers well-drained, lean to moderately fertile soil; it tolerates sandy, rocky, or even clay soils as long as drainage is excellent.
- ✓ Watering — Highly drought-tolerant once established; water sparingly, allowing soil to dry out completely between waterings. Overwatering can lead to root rot.
- ✓ Propagation — Can be propagated by seed (sow in fall or early spring) or by division of established clumps in spring or fall.
- ✓ Spacing — Plant individual specimens 12-18 inches apart to allow for its sprawling growth habit.
- ✓ Maintenance — Low maintenance; deadhead spent flowers to encourage continuous blooming and prevent self-seeding, though its large seed pods are also ornamental.
- ✓ Fertilization — Generally does not require fertilization, especially in lean soils; excessive nutrients can lead to leggy growth and fewer flowers.
- ✓ Pest and Disease — Highly resistant to most common pests and diseases, thriving in challenging conditions.
Reviewed by the Flora Medical Global Botanical Review Panel
Multi-disciplinary editorial group · Botany · Ethnobotany · Herbal-medicine literature
Who reviewed this: This page was checked by the Flora Medical Global Botanical Review Panel — an in-house editorial group of botany graduates, ethnobotany researchers, and horticulture practitioners who collectively maintain our 7,000+ plant encyclopedia. Meet the team.
Our 4-step verification process
1. Taxonomic verification
Scientific names and synonyms cross-checked against Kew POWO, World Flora Online, and The Plant List.
2. Phytochemical & medicinal cross-reference
Active compounds, traditional uses, and reported activities are cross-referenced with PubMed, USDA Dr. Duke's database, and peer-reviewed ethnobotanical literature.
3. Conservation & distribution check
Distribution, ecology, and conservation status confirmed against GBIF occurrence records and the IUCN Red List.
4. Editorial & safety review
Every entry passes an editorial pass for clarity, originality, and safety notices (toxicity, contraindications, dosage caveats) before publication.
Last reviewed:
Editorial Note: This page is for educational and plant care purposes only.
Written by: Flora Medical Global Editorial Team
Reviewed by: Flora Medical Global Botanical Review Panel
Last Updated: June 19, 2026
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