Rosemary in Zone 5a & 5b
Salvia rosmarinus
Yes, rosemary grows in zones 5a and 5b. Start seeds indoors Mar 1–Mar 8 and plant out May 24–May 31.
When to plant rosemary in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 1–Mar 8 |
|---|---|
| Direct sow / transplant outside | May 24–May 31 |
| Estimated harvest | Aug 22–Aug 29 (~90 days after transplanting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-4 ft.
Plant alongside it in zone 5b
These go outside within two weeks of rosemary in zone 5b, so one planting day can cover them.
- BasilMay 24–May 31
- BorageMay 10–May 17
- SageMay 24–May 31
- TobaccoMay 24–May 31
- Za'atar OreganoMay 24–May 31
- CatmintMay 17–May 24
Rosemary is a woody Mediterranean shrub, not a tender annual herb. Treat it more like a small perennial landscape plant than something you replant every spring. In the right climate, one plant can keep producing for years.
How rosemary fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Rosemary needs about 90 days from transplant to first harvest.
Rosemary 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 | Harvest |
|---|---|---|---|
| 4a & 4b | Mar 6–Mar 13 | May 29–Jun 5 | Aug 27–Sep 3 |
| 5a & 5b (your zone) | Mar 1–Mar 8 | May 24–May 31 | Aug 22–Aug 29 |
| 6a & 6b | Feb 14–Feb 21 | May 9–May 16 | Aug 7–Aug 14 |
| 7a & 7b | Jan 30–Feb 6 | Apr 24–May 1 | Jul 23–Jul 30 |
| 8a & 8b | Jan 14–Jan 21 | Apr 8–Apr 15 | Jul 7–Jul 14 |
| 9a & 9b | Dec 7–Dec 14 | Mar 1–Mar 8 | May 30–Jun 6 |
| 10a & 10bSpring window | Not usually | Feb–Apr | ~90 days after transplanting |
| Fall window | Not usually | Oct–Nov | ~90 days after transplanting |
| 11a & 11b | Oct 23–Oct 30 | Jan 15–Jan 22 | Apr 15–Apr 22 |
Harvest dates are about 90 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
- Cabbage: Rosemary's scent is reputed to deter cabbage moths, the same role thyme and sage play, though rosemary itself hasn't been specifically tested the way thyme and sage have: treat this as garden tradition rather than a directly measured result.
Where to buy rosemary seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's rosemary seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing rosemary" 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 Rosemary in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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