Hollyhock in Zone 10a & 10b
Alcea rosea
Yes, hollyhock grows in zones 10a and 10b. Start seeds indoors in Aug–Jan and plant out in Oct–Mar. For a fall crop, start seeds indoors in Aug–Jan and plant out in Oct–Mar.
When to plant hollyhock in zone 10b
Zones 10a and 10b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. In your zone it 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 | ~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.
Fall window: the last sowing date is the average first frost minus days to maturity, the method in Purdue Extension's fall garden guide, which lists hollyhock for late-summer planting.
Plant alongside it in zone 10b
These go outside within two weeks of hollyhock in zone 10b, so one planting day can cover them.
- Black-Eyed SusanOct–Mar
- Love-in-a-Mist (Nigella)Oct–Mar
- Pansy / ViolaOct–Jan
- RanunculusOct–Nov
- StrawflowerOct–Feb
- Sweet AlyssumOct–Mar
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 goes in during the fall and grows through the winter, so it isn't limited by this window: expect first bloom about 180 days after planting.
Hollyhock planting windows in every zone
Zone 10b 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 | Not usually | May 16–May 23 | Nov 12–Nov 19 |
| 4a & 4b | Not usually | May 1–May 8 | Oct 28–Nov 4 |
| 5a & 5b | Not usually | Apr 26–May 3 | Oct 23–Oct 30 |
| 6a & 6b | Not usually | Apr 11–Apr 18 | Oct 8–Oct 15 |
| 7a & 7b | Not usually | Mar 27–Apr 3 | Sep 23–Sep 30 |
| 8a & 8b | Not usually | Mar 11–Mar 18 | Sep 7–Sep 14 |
| 9a & 9b | Not usually | Feb 1–Feb 8 | Jul 31–Aug 7 |
| 10a & 10bFall window (your zone) | Aug–Jan | Oct–Mar | ~180 days after transplanting |
Bloom dates are about 180 days after the sow or plant-out date.
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
Botanical Interests · True Leaf Market · Burpee (each supplier's hollyhock seeds)
Varieties we recommend, and where to get them:
- Alcea rosea 'Nigra': Missouri Botanical Garden describes deep maroon blooms that look almost black, on rigid 5-8 foot spikes that typically don't need staking. Buy: True Leaf Market Full notes
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 · 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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