Gadenin日本語Get the appThe year at a glance
Evening primroses ask for little attention once they are in the right spot. Most of the work falls in late winter and spring, when you sow and move young plants, and in autumn, when you save seed for next year.
| Season | Main jobs |
|---|---|
| Late winter | Sow refrigerated seed indoors or in a cold frame |
| Early spring | Move seedlings at 1-2 true leaves; divide showy evening primrose |
| Mid to late spring | Pot up; harden off and plant out; stake tall kinds |
| Summer | Flowering; watch for flea beetles; water pots only |
| Autumn | Collect seed capsules; divide showy evening primrose if needed |
| Winter | Light protection in cold spots; keep alpine kinds dry |
Late winter and spring: sowing and planting out
Take the seed saved in autumn out of the refrigerator in late winter and sow it thinly in a gritty seed mix. As soon as seedlings have one or two true leaves, move them into deep cells or small pots without damaging the root, and pot them up two or three times as they grow.
In mid to late spring, once the soil has warmed and hard frosts are over, harden plants off and set them out in full sun in raised, free-draining ground. Put supports in for O. stricta and O. glazioviana before they get tall. Established clumps of showy evening primrose can be divided as new shoots appear.
- Sow Late winter to early spring, at about 60 to 70°F (15 to 21°C). Germination usually takes two to three weeks.
- Move on At one or two true leaves, lift gently into deep pots, then pot up as roots fill each pot.
- Plant out After the last hard frost, in the sunniest, best-drained spot, with the root ball left intact.
Summer: flowers and flea beetles
This is the season of flowers. Night bloomers open at dusk, the day-blooming kinds through the daylight hours, over many weeks. Water plants in containers when the surface dries out; leave plants in the ground alone except in a long drought. Do not feed. Check leaves every few days for flea beetles and knock them into a dish when you see them.
Autumn and winter: seed and rest
As capsules brown and start to split in autumn, gather them for seed, and leave a few on the plants if you are happy for them to self-sow. Cut back spent stems once you have what you need. Large-flowered O. glazioviana will die after seeding, so make sure its seedlings or saved seed are there to replace it.
Over winter, evening primroses need little. In cold, exposed spots lay a light covering of evergreen boughs over the crowns; most plants are hardy without it. Keep O. acaulis and O. caespitosa dry under a cloche or pane of glass, and store your seed in the refrigerator until late winter comes around again.
First-year seedlings of most kinds spend their first season as a flat rosette. Do not give up on them: the flowers come the following year.