Clustered bellflower
Campanula glomerata
A sturdy, upright hardy perennial grown for the dense terminal heads — and tight axillary clusters — of upward- and outward-facing, deep violet-blue (sometimes white or purple) bell-shaped flowers it carries from early to midsummer above clumps of rough, oval basal leaves. POWO (Kew) gives its native range as a broad sweep of the temperate Northern Hemisphere from Britain across Europe and through temperate Asia to Japan and Korea (some 57 botanical countries), where it grows in dry grassland, scrub, and open woodland, often on chalky soils. It is one of the easiest border bellflowers: hardy in USDA zones 3a-8b and rated fully hardy (H7) by the RHS, which gives the rich-blue cultivar "Superba" and the pale "Caroline" its Award of Garden Merit. Plant it in full sun or light shade in ordinary, moisture-retentive soil and it will spread steadily by underground rhizomes to form a colony — vigorous and welcome in a relaxed border, but worth siting where it can run, or lifting and dividing to keep it in bounds. The open clusters are excellent for bees, worked above all by bumblebees. Sources give no edible use, so treat it as an ornamental only.
Climate fit: moderate (47/100)
Border
Pollinator
Filler
Light
Full sun / Part shade
Water
Moderate water
Mature size
12-24" tall · 15" apart
Hardy in zones
3a-8b
brutally cold to frosty winters
Native in Illinois
No
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The dense clusters of open, outward- and upward-facing bells are excellent for bees and draw honey bees and solitary bees for nectar and pollen, but they are worked above all by bumblebees, which climb into the cups to reach the nectar at the base.
Cold hardiness
These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Well-suited
Zone 7a
Plotwright
0°F to 5°F
Well-suited
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
✓
Well-suited today and still thriving in 2050.
Heat tolerance
Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...
Where this plant fits
Suitable across 40 ecoregions — 35 climate-resilient through 2070 · 5 suited today. Best matches first.
Appalachian mixed mesophytic forests
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Appalachian-Blue Ridge forests
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Arizona Mountains forests
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Blue Mountains forests
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Canadian Aspen forests and parklands
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Central Pacific Northwest coastal forests
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Central Tallgrass prairie
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Central-Southern Cascades Forests
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Colorado Rockies forests
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Cross-Timbers savanna-woodland
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Similar plants
Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
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Common primrose
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Galanthus nivalis
Common snowdrop
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The classic lawn daisy: a low, rosette-forming perennial with spoon-shaped leaves and white, often pink-tipped ray flowers around a yellow disc on short stems, blooming from spring into autumn. The flowers close at night and in rain — the old "day's eye" — and double cool-season bedding forms such as "Pomponette" and "Habanera" are widely grown. Often written off as a lawn weed, it is in fact a tough, charming, child's-favourite groundcover that flowers for months, thrives in mown grass because it keeps its blooms low, and offers easy early-season nectar and pollen. The flowers and young leaves are edible.
Educator packet
Plant packet
Clustered bellflower educator packet
A sturdy, upright hardy perennial grown for the dense terminal heads — and tight axillary clusters — of upward- and outward-facing, deep violet-blue (sometimes white or purple) bell-shaped flowers it carries from early to midsummer above clumps of rough, oval basal leaves. POWO (Kew) gives its native range as a broad sweep of the temperate Northern Hemisphere from Britain across Europe and through temperate Asia to Japan and Korea (some 57 botanical countries), where it grows in dry grassland, scrub, and open woodland, often on chalky soils. It is one of the easiest border bellflowers: hardy in USDA zones 3a-8b and rated fully hardy (H7) by the RHS, which gives the rich-blue cultivar "Superba" and the pale "Caroline" its Award of Garden Merit. Plant it in full sun or light shade in ordinary, moisture-retentive soil and it will spread steadily by underground rhizomes to form a colony — vigorous and welcome in a relaxed border, but worth siting where it can run, or lifting and dividing to keep it in bounds. The open clusters are excellent for bees, worked above all by bumblebees. Sources give no edible use, so treat it as an ornamental only.
Scientific name
Campanula glomerata
Plant type
perennial
Hardiness
3a-8b
Light
full-sun, part-shade
Moisture
moderate
Spacing
15 inches
Classroom prompts
- Which plant traits are observations, and which are care recommendations?
- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?
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Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Clustered bellflower (Campanula glomerata). Retrieved 2026, June 27, from https://plotwright.com/plants/campanula-glomerata
Sources for every fact
Every fact on this page traces to a source. 18 fields cited - 18 source-backed.
Plants of the World Online (POWO)
Botanical research database
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
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