California Bluebell in Zone 10a & 10b
Phacelia campanularia
Yes, California bluebell grows in zones 10a and 10b. Plant it outside Jan 30–Feb 6.
When to plant California bluebell in zone 10b
Zones 10a and 10b 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 | Jan 30–Feb 6 |
| Estimated bloom | Apr 10–Apr 17 (~70 days after direct-sowing) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Plant alongside it in zone 10b
These go outside within two weeks of California bluebell in zone 10b, so one planting day can cover them.
- MarigoldFeb–May
- African DaisyJan 30–Feb 6
- Amaranthus (Love-Lies-Bleeding)Jan 30–Feb 6
- Ammi (False Queen Anne's Lace)Jan 30–Feb 6
- Ammobium (Winged Everlasting)Jan 30–Feb 6
- Carthamus (Safflower)Jan 30–Feb 6
California bluebell is a desert native that flowers hard for about a month and then finishes, which makes it a spring crop rather than a summer one.
How California bluebell fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. California bluebell needs about 70 days from sowing to first bloom.
California Bluebell 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 |
|---|---|---|---|
| 2a & 2b | Not usually | May 20–May 27 | Jul 29–Aug 5 |
| 3a & 3b | Not usually | May 30–Jun 6 | Aug 8–Aug 15 |
| 4a & 4b | Not usually | May 15–May 22 | Jul 24–Jul 31 |
| 5a & 5b | Not usually | May 10–May 17 | Jul 19–Jul 26 |
| 6a & 6b | Not usually | Apr 25–May 2 | Jul 4–Jul 11 |
| 7a & 7b | Not usually | Apr 10–Apr 17 | Jun 19–Jun 26 |
| 8a & 8b | Not usually | Mar 25–Apr 1 | Jun 3–Jun 10 |
| 9a & 9b | Not usually | Feb 15–Feb 22 | Apr 26–May 3 |
| 10a & 10b (your zone) | Not usually | Jan 30–Feb 6 | Apr 10–Apr 17 |
Bloom dates are about 70 days after the sow or plant-out date.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
No well-established companions for California bluebell.
Where to buy California bluebell seeds
Botanical Interests (California bluebell seeds)
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See it growing
Search YouTube for "growing California bluebell" 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 California Bluebell in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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