Dahlia in Zone 11a & 11b
Dahlia spp.
When to plant dahlia in zone 11b
Zones 11a and 11b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Dahlia doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Jan 15–Jan 22 |
| Estimated bloom | Apr 15–Apr 22 (~90 days after direct-sowing) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-5 ft.
Dahlia is the one flower in this garden that doesn't start as seed at all. It grows from a tuber, planted like a potato, which changes the whole rhythm of how it goes in the ground and comes out at season's end. Blooms run from small pompoms to dinner-plate-sized flower heads, in nearly every color except true blue, on plants that range from 1 to 5 feet depending on type.
How dahlia fits zone 11's season
Zone 11b is frost-free in this dataset, so frost is not what limits the calendar here. What you can plant, and when, comes down to summer heat and daylength instead.
Good companions
No standout companions recorded yet for Dahlia.
Where to buy dahlia bulbs
We haven't vetted bulb/tuber suppliers yet. Our seed-supplier list below doesn't carry these. The growing-guide source cited above is a good starting point for where to buy.
See it growing
Search YouTube for "growing dahlia" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 11b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Dahlia in USDA zone 11b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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