Showy Evening Primrose in Zone 5a & 5b
Oenothera speciosa
Yes, showy evening primrose grows in zones 5a and 5b and comes back each year. Plant it outside May 10–May 17.
When to plant showy evening primrose in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 10–May 17 |
| Estimated bloom | First real harvest the season after planting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Before you plant: Showy evening primrose has a winter-hardiness note for zone 5b. See the details below.
Plant alongside it in zone 5b
These go outside within two weeks of showy evening primrose in zone 5b, so one planting day can cover them.
- NasturtiumMay 17–May 24
- MarigoldMay 17–May 24
- African DaisyMay 10–May 17
- Amaranthus (Love-Lies-Bleeding)May 10–May 17
- Ammi (False Queen Anne's Lace)May 10–May 17
- Ammobium (Winged Everlasting)May 10–May 17
Showy evening primrose is the most aggressive plant here, and the extension source says so directly rather than hinting at it.
How showy evening primrose fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Showy evening primrose takes about 1 growing season to reach full flowering, so what matters here is how many of these seasons it gets, not whether one is long enough.
Showy evening primrose is hardy in zones 5-8, so in zone 5b it stays in the ground through winter and comes back rather than being replanted. Allow about 2 ft of spread at maturity.
Showy Evening Primrose planting windows in every zone
Zone 5b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 5a & 5b (your zone) | Not usually | May 10–May 17 | First real harvest the season after planting |
| 6a & 6b | Not usually | Apr 25–May 2 | First real harvest the season after planting |
| 7a & 7b | Not usually | Apr 10–Apr 17 | First real harvest the season after planting |
| 8a & 8b | Not usually | Mar 25–Apr 1 | First real harvest the season after planting |
Good companions
No well-established companions for showy evening primrose.
Where to buy showy evening primrose seeds
None of the seed suppliers we list carries showy evening primrose seeds right now. A local garden center or a specialty seed house is the place to look.
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing showy evening primrose" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Plan your beds in the Garden Designer →
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Growing Showy Evening Primrose in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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