Yarrow in Zone 5a & 5b
Achillea millefolium
Yes, yarrow grows in zones 5a and 5b. Start seeds indoors Mar 8–Mar 15 and plant out May 10–May 17.
When to plant yarrow in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
| Start indoors | Mar 8–Mar 15 |
|---|---|
| Direct sow / transplant outside | May 10–May 17 |
| Estimated bloom | Aug 18–Aug 25 (~100 days after planting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.
Plant alongside it in zone 5b
These go outside within two weeks of yarrow 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

Yarrow is a hardy perennial known for its flat-topped flower clusters and its toughness once established. It tolerates poor soil, drought, and deer browsing better than most garden flowers.
How yarrow fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Yarrow needs about 100 days from sowing to first bloom.
Yarrow 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 |
|---|---|---|---|
| 3a & 3b | Mar 28–Apr 4 | May 30–Jun 6 | Sep 7–Sep 14 |
| 4a & 4b | Mar 13–Mar 20 | May 15–May 22 | Aug 23–Aug 30 |
| 5a & 5b (your zone) | Mar 8–Mar 15 | May 10–May 17 | Aug 18–Aug 25 |
| 6a & 6b | Feb 21–Feb 28 | Apr 25–May 2 | Aug 3–Aug 10 |
| 7a & 7b | Feb 6–Feb 13 | Apr 10–Apr 17 | Jul 19–Jul 26 |
| 8a & 8b | Jan 21–Jan 28 | Mar 25–Apr 1 | Jul 3–Jul 10 |
| 9a & 9b | Dec 14–Dec 21 | Feb 15–Feb 22 | May 26–Jun 2 |
Bloom dates are about 100 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
No well-established companions for yarrow.
Where to buy yarrow seeds
True Leaf Market · High Mowing Organic Seeds (each supplier's yarrow seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing yarrow" 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 Yarrow in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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