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Evening Primrose

Oenothera biennis
Also known as: Common Evening Primrose, Sundrops, Suncups, Tree Primrose

Evening Primrose is a herb in the Onagraceae family. It grows best in full sun to part shade with dry to medium moisture, and is listed for USDA zones 4-9. Plants reach harvest about 620–840 days after planting and sit about 12 inches apart.

Varieties

1 from Seeds Now · sorted by days to maturity
  • King’s Cure-All620–840 days

    The night-flowering Evening Primrose (Oenothera biennis) has delicate four-petal lemon-scented lemon-yellow 2" blossoms that close every day by noon, opening again in the late afternoon and evening. Plants grow 2'-6' tall on hairy stems tinged with purple. Also called King’s Cure-All for its herbal and medicinal properties. Life cycle: Biennial Bloom season: Spring, summer, fall Attracts: Birds, bees, butterflies, moths, and other pollinators Flower meaning: Bashfulness, inconstancy, longevity, youth

    Growing notes: Botanical name: Oenothera biennis|Hardiness zones: 4-9|Planting season: Spring, summer|Days to maturity: 2nd year|Cold stratify: Yes|Depth to plant seeds: Lightly cover - seeds need light to germinate|Spacing between plants: 12"-18" apart|Days to germinate (sprout): 15-30 days|Germination soil temps: 65F-70F|Soil types: Sandy, loamy, rich, well-drained|Soil pH: 5.5-7.5|Water needs: Average|Sun needs: Full sun, part shade|Frost tolerant: No|Drought tolerant: Yes|Deer resistant: Yes

    View on Seeds Now
Family
Onagraceae
Category
Herb
Form
Bush
Lifecycle
biennial
Zone
4-9
Height
3–5 ft
Spread
1–2 ft
Sun
Full sun to part shade

Plant spacing

1 plant per square footSquare-foot planting diagram: one evening primrose fills a 1-foot square, spaced 12 inches from its neighbors.
1 plant per square foot

In a square-foot bed, space evening primrose about 12 in apart — that fits 1 plant in each 1-foot square (1×1). Wider rows or containers space the same.

Water
Dry to medium

Plan your evening primrose planting

Add evening primrose to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.

Start your free plan →

At a glance

Days to harvest
620–840 days
From transplant or sow to first harvest
Harvest style
Keep picking
Crops over several weeks
Frost tolerance
Hardy · to ~15°F
Lowest temperature the foliage usually survives

Storing & preserving

Refrigerate stems in water, or wrap in a damp towel for a few days.

  • Dry: Dehydrate or air-dry, then store airtight away from light.
  • Freeze: Freeze chopped in oil or water in ice-cube trays.

General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.

Growing timeline

When to plant and harvest evening primrosePlanting timeline for evening primrose, relative to last frost: start indoors from 10 weeks before last frost to 2 weeks before last frost; grow from 2 weeks before last frost to 87 weeks after last frost; harvest from 87 weeks after last frost to 118 weeks after last frost.GrowHarvestLast frostTransplant
Start evening primrose indoors ~8 weeks before transplanting 2 weeks before last frost; first harvest 87 weeks after last frost.
Seed to transplant
42-56 days
Outdoor planting
-14 to 0 days vs frost
Propagation
Seed
Schedule anchor
Last Frost

Care & troubleshooting

No curated care & troubleshooting advice for evening primrose yet. Our extension-sourced library currently focuses on common edible crops; we're expanding it over time.