Campanula (Bellflower) in Zone 9a & 9b

Campanula medium

When to plant campanula (bellflower) in zone 9b

Zones 9a and 9b share the same average frost dates in our data, so this page covers both.

Method: Start indoors: Start indoors from seed, then transplant outside. Campanula (Bellflower) needs a head start most zones can't give it by direct-sowing alone.

Start indoorsDec 28–Jan 4 '27
Direct sow / transplant outsideFeb 22–Mar 1
Estimated bloomJun 22–Jun 29 (~120 days after transplanting)

Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 2.5-3.5 ft.

Campanula (Bellflower)
Photo: Salicyna via Wikimedia Commons, CC BY-SA 4.0, cropped.

Campanula, also called Canterbury bells, is a tall spring cut flower with a genuine quirk: it's daylength-sensitive, needing short days as a young seedling to build enough stem length before it flowers under the long days of early summer.

How campanula (bellflower) fits zone 9's season

Zone 9b's frost-free window runs about 293 days, from February 15 to December 5. Campanula (Bellflower) needs about 120 days from transplant to first harvest.

Good companions

No standout companions recorded yet for Campanula (Bellflower).

Where to buy campanula seeds

See why we recommend these suppliers →

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See it growing

Search YouTube for "growing campanula (bellflower)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

← Back to the full zone 9b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

Growing Campanula (Bellflower) in USDA zone 9b

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Growing Campanula (Bellflower) in USDA zone 9b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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