Oenothera speciosa (Showy Evening Primrose)

Seed Treatment (Pre-Sowing)

  • COLD STRATIFICATION:

    1. Place seeds in a damp paper towel or mix with moist vermiculite.
    2. Seal in a plastic bag and refrigerate for 2–4 weeks at 40°F (4°C).
    3. After stratification, sow as normal.

  • Optional soaking: For faster germination, soak seeds in warm water for 12–24 hours before sowing.

? Sowing Instructions

  • When to sow outdoors: Late fall (for natural stratification) or early spring.

  • When to sow indoors: 6–8 weeks before last expected frost date.

  • Seed depth: Do not cover deeply. Sow on the surface or lightly press into soil — seeds need light to germinate.

  • Spacing: Space plants 12–18 inches (30–45 cm) apart.

  • Germination time: Usually 10–30 days, but allow up to 45 days.

  • Germination temperature: Ideal is 65–75°F (18–24°C).

☀️ Growing Conditions

  • Sunlight: Full sun preferred; tolerates partial shade.

  • Soil: Well-drained sandy or loamy soil. Tolerates poor soils.

  • Water:  Keep moist during germination. Once established, drought-tolerant.

  • USDA Zones: 4–9. May die back in winter but returns in spring.

? Additional Tips

  • Deadhead to prolong blooming and limit aggressive self-seeding.
  • Great for wildflower gardens, borders, and naturalized spaces.
  • Attracts bees, butterflies, and other pollinators.

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