Scarlet Flax in Zone 4a & 4b
Linum grandiflorum
Yes, scarlet flax grows in zones 4a and 4b. Plant it outside May 15–May 22.
When to plant scarlet flax in zone 4b
Zones 4a and 4b 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 15–May 22 |
| Estimated bloom | Jul 24–Jul 31 (~70 days after direct-sowing) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1-1.5 ft.
Plant alongside it in zone 4b
These go outside within two weeks of scarlet flax in zone 4b, so one planting day can cover them.
- NasturtiumMay 22–May 29
- MarigoldMay 22–May 29
- African DaisyMay 15–May 22
- Amaranthus (Love-Lies-Bleeding)May 15–May 22
- Ammi (False Queen Anne's Lace)May 15–May 22
- Ammobium (Winged Everlasting)May 15–May 22
Scarlet flax is a wispy annual whose individual flowers last a single day. The plant compensates by producing a great many of them.
How scarlet flax fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Scarlet flax needs about 70 days from sowing to first bloom.
Scarlet Flax planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 4a & 4b (your zone) | Not usually | May 15–May 22 | Jul 24–Jul 31 |
| 5a & 5b | Not usually | May 10–May 17 | Jul 19–Jul 26 |
| 6a & 6b | Not usually | Apr 25–May 2 | Jul 4–Jul 11 |
| 7a & 7b | Not usually | Apr 10–Apr 17 | Jun 19–Jun 26 |
| 8a & 8b | Not usually | Mar 25–Apr 1 | Jun 3–Jun 10 |
| 9a & 9b | Not usually | Feb 15–Feb 22 | Apr 26–May 3 |
Bloom dates are about 70 days after the sow or plant-out date.
Good companions
No well-established companions for scarlet flax.
Where to buy scarlet flax seeds
Botanical Interests · True Leaf Market (scarlet flax seeds)
See why we recommend these suppliers →
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a clear consensus of positive, independent reviews, or ones we bought and use ourselves. Each item on our gear page says which.
See it growing
Search YouTube for "growing scarlet flax" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
Pin this for later
Growing Scarlet Flax in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
Save to Pinterest