How to Grow Evening Primrose
Evening Primrose At a Glance
Difficulty
Easy
Category
Flower
Sun Exposure
Full Sun, Partial Sun
Frost Tolerance
Frost Hardy
Cold Hardiness
Survives to -29°C
Plant Family
Onagraceae
Growing Season
Warm Season
Plant Lifecycle
Biennial
How to Start It
★ Recommended for beginners
Sow in late fall and let winter do the work, or in early spring, about 4 weeks before your last frost. Scatter the tiny seeds right where they will grow, since the plant has one long main root and hates being moved, and cover them no more than 0.5 cm because they need light to sprout. They take 10 to 30 days to come up: thin them (pull the extras so each has room) to 30 cm apart.
Evening primrose makes a low circle of leaves in its first year, then tall stems of yellow flowers in its second year that open in the evening and smell sweet to draw in moths. After it sets seed the plant dies, but it drops so much seed that new plants come up every year on their own.
When To Start
First chance to plant
30 Days Before Last Frost
Last chance to plant
56 Days Before First Frost
When should you plant Evening Primrose?
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Your Evening Primrose Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Evening Primrose Calendar
Set your location to turn these into exact dates and reminders.
Sow evening primrose on the surface, flowers come next year
30 days before your last frost· every year
Did you water your evening primrose seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Hello from your growing space! Keep the soil lightly moist while your evening primrose settles in.
About 30 days after you plant it
Nice work so far. Thin crowded seedlings so each evening primrose has room to form a leafy rosette.
About 90 days after you plant it
Picking time may be here: check your evening primrose.
About 365 days after you plant it
The Journey Ahead
Evening Primrose's Lifecycle
Seedling
Mature Plant
Seed Production
Step 1
Prepare Your Space
0.5 cm
Seeding Depth
30 cm
Plant Spacing
45 cm
Row Spacing
1
Plants / Sq Ft
Vertical Growing
Yes: Trellis.
Method: Trellis.
Succession Planting
Yes
Good Companions
Bad Companions
Step 2
Planting & Sprouting
Expect sprouts in 10–30 days
Growing Tips
- 1Grow evening primrose in full sun.
- 2It likes poor, dry, well-drained soil, so skip the compost and avoid soggy spots.
- 3Water seedlings until they are growing well, then only in long dry spells.
- 4Do not feed it, because rich soil gives floppy stems and fewer flowers.
- 5Knock aphids off with a spray of water, and cover young plants with row cover if flea beetles (tiny jumping beetles) chew small holes in the leaves.
- 6Pull unwanted seedlings while they are small, since it spreads freely.
Seedling Phase
Step 3
Growth & Maturity
~365
Days to Maturity
120 cm
Mature Height
60 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
Harvest Window
21 days
When to Pick
Harvest evening primrose seeds in late summer to early fall when the seed pods turn brown and begin to split. Cut the seed pods from the plant, place them in a paper bag, and allow them to dry in a cool, dry place. Once fully dry, shake or crush the pods to release the seeds. Collect and store seeds in an airtight container.
How to Harvest
- 1Enjoy the flowers on summer evenings, since each one opens at dusk and fades by the next afternoon.
- 2Cut off faded flower stems before the pods ripen if you do not want new plants everywhere.
- 3Leave some pods on the stems if you want new plants, since the seeds also feed goldfinches and other small birds in winter.
- 4Pull out each plant once its pods have dried and opened, because it dies after flowering anyway.
Step 5
Saving Seeds
How to Save Seeds
Evening primrose mostly pollinates itself, so its seeds come true. Wait until the long pods along the stem turn brown and dry and begin to split at the top. Cut the stems into a paper bag, let them dry for a week, then shake the bag so the tiny seeds fall out. Store them labelled in a cool, dark, dry place, where they keep for several years. For a spring sowing, mix the seeds with damp sand in a bag and keep it in the fridge for 4 weeks first, which helps them sprout.
Seed Production
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