Hollyhock in Zone 10a & 10b
Alcea rosea
When to plant hollyhock in zone 10b
Zones 10a and 10b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. In your zone, Hollyhock needs a head start on the heat that direct-sowing elsewhere doesn't require.
| Window | Fall window |
|---|---|
| Start indoors | Aug–Jan |
| Direct sow / transplant outside | Oct–Mar |
| Estimated bloom | Mar 30 '27–Sep 27 '27 (~180 days after transplanting) |
Spacing: about 5 square feet per plant (square-foot-gardening spacing). Mature height: 5-9 ft.
Zone 10b dates sourced from growinginthegarden.com.
Hollyhock is a garden fixture that asks for patience and plenty of vertical space. It's a biennial in most climates, meaning it spends its first year just building a rosette of leaves and doesn't bloom until the second, and by the time it does, it can tower up to 9 feet.
How hollyhock fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Hollyhock needs about 180 days from sowing to first harvest.
Good companions
- Nasturtium: Planted at hollyhock's base, reputed to help suppress hollyhock rust, but no research or extension source was found testing this specific pairing — treat it as garden tradition, not measured evidence.
- Garlic: Planted at hollyhock's base, reputed to help suppress rust via antifungal root secretions, but no research or extension source was found testing this specific pairing — treat it as garden tradition, not measured evidence.
Where to buy hollyhock seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing hollyhock" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Hollyhock in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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