Heuchera (Coral Bells) in Zone 4a & 4b
Heuchera americana
Yes, heuchera (coral bells) grows in zones 4a and 4b and comes back each year. Plant it outside May 1–May 8.
When to plant heuchera (coral bells) 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 1–May 8 |
| Estimated bloom | First real harvest the season after planting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.
Before you plant: Heuchera (coral bells) has a winter-hardiness note for zone 4b. See the details below.
Plant alongside it in zone 4b
These go outside within two weeks of heuchera (coral bells) in zone 4b, so one planting day can cover them.
- Agrostemma (Corn Cockle)May 1–May 8
- AstilbeMay 1–May 8
- Bachelor's Button (Cornflower)May 1–May 8
- Basket-of-GoldMay 1–May 8
- Bupleurum (Thoroughwax)May 1–May 8
- CalendulaMay 1–May 8
Heuchera is grown for leaf colour that holds most of the year, in a range from lime green through caramel to something close to black.
How heuchera (coral bells) fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Heuchera (coral bells) 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.
Heuchera (coral bells) is hardy in zones 4-9, so in zone 4b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.5 ft of spread at maturity.
Heuchera (Coral Bells) 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 1–May 8 | First real harvest the season after planting |
| 5a & 5b | Not usually | Apr 26–May 3 | First real harvest the season after planting |
| 6a & 6b | Not usually | Apr 11–Apr 18 | First real harvest the season after planting |
| 7a & 7b | Not usually | Mar 27–Apr 3 | First real harvest the season after planting |
| 8a & 8b | Not usually | Mar 11–Mar 18 | First real harvest the season after planting |
| 9a & 9b | Not usually | Feb 1–Feb 8 | First real harvest the season after planting |
Good companions
No well-established companions for heuchera (coral bells).
Where to buy heuchera seeds
True Leaf Market (each supplier's heuchera seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing heuchera (coral bells)" 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 →
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Growing Heuchera (Coral Bells) in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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