Impatiens in Zone 3a & 3b
Impatiens walleriana
Yes, impatiens grows in zones 3a and 3b. Start seeds indoors Mar 21–Mar 28 and plant out Jun 13–Jun 20.
When to plant impatiens in zone 3b
Zones 3a and 3b 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 21–Mar 28 |
|---|---|
| Direct sow / transplant outside | Jun 13–Jun 20 |
| Estimated bloom | Aug 27–Sep 3 (~75 days after transplanting) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 0.5-2 ft.
Plant alongside it in zone 3b
These go outside within two weeks of impatiens in zone 3b, so one planting day can cover them.
- NasturtiumJun 6–Jun 13
- MarigoldJun 6–Jun 13
- Angelonia (Summer Snapdragon)Jun 13–Jun 20
- Black-Eyed Susan VineJun 13–Jun 20
- Cleome (Spider Flower)Jun 13–Jun 20
- ColeusJun 13–Jun 20
Impatiens flowers reliably in shade, which almost nothing else here does. It also carries a disease problem worth understanding before you plant a whole bed of it.
How impatiens fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Impatiens needs about 75 days from transplant to first bloom.
Impatiens planting windows in every zone
Zone 3b 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 (your zone) | Mar 21–Mar 28 | Jun 13–Jun 20 | Aug 27–Sep 3 |
| 4a & 4b | Mar 6–Mar 13 | May 29–Jun 5 | Aug 12–Aug 19 |
| 5a & 5b | Mar 1–Mar 8 | May 24–May 31 | Aug 7–Aug 14 |
| 6a & 6b | Feb 14–Feb 21 | May 9–May 16 | Jul 23–Jul 30 |
| 7a & 7b | Jan 30–Feb 6 | Apr 24–May 1 | Jul 8–Jul 15 |
| 8a & 8b | Jan 14–Jan 21 | Apr 8–Apr 15 | Jun 22–Jun 29 |
| 9a & 9b | Dec 7–Dec 14 | Mar 1–Mar 8 | May 15–May 22 |
| 10a & 10b | Nov 21–Nov 28 | Feb 13–Feb 20 | Apr 29–May 6 |
| 11a & 11b | Oct 23–Oct 30 | Jan 15–Jan 22 | Mar 31–Apr 7 |
Bloom dates are about 75 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
No well-established companions for impatiens.
Where to buy impatiens seeds
True Leaf Market · Burpee (each supplier's impatiens seeds)
Varieties we recommend, and where to get them:
- Beacon series (best for downy mildew resistance): Bred by PanAmerican Seed and described by Illinois Extension and NC State Extension as highly resistant to impatiens downy mildew, the disease that wiped bedding impatiens out of many gardens. Buy: Burpee Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing impatiens" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Plan your beds in the Garden Designer →
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Growing Impatiens in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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