Foxglove in Zone 4a & 4b
Digitalis purpurea
When to plant foxglove in zone 4b
Zones 4a and 4b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. Foxglove needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Feb 27–Mar 6 |
|---|---|
| Direct sow / transplant outside | May 22–May 29 |
| Estimated bloom | May 21 '28–May 28 '28 (~365 days after transplanting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-5 ft.
Foxglove produces some of the most dramatic flower spikes of any garden biennial, tall stalks lined with tubular, often speckled blooms. It's also the source of digoxin, a real heart medication, which is a way of saying every part of this plant is toxic if eaten, not just mildly irritating.
How foxglove fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Foxglove needs about 365 days from transplant to first harvest.
Good companions
No standout companions recorded yet for Foxglove.
Where to buy foxglove seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing foxglove" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Foxglove in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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