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Clustered bellflower

Hans Hillewaert / Wikimedia Commons - CC BY-SA 3.0

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

Related products

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

2050

2100

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 42 ecoregions - 34 climate-resilient through 2070 · 5 suited today · 3 newly possible by 2070. 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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Atlantic coastal pine barrens

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Blue Mountains forests

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Central Pacific Northwest coastal forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

What it needs

Conditions

Light

Full sun / Part shade

Water

Moderate water

Spacing

15"

Habit

Upright, clump-forming and steadily spreading perennial that makes clumps of rough, oval, slightly hairy basal leaves and erect, leafy flowering stems topped from early to midsummer with dense rounded heads of upward- and outward-facing, deep violet-blue (sometimes white or purple) bell-shaped flowers, with further tight clusters in the upper leaf axils. It runs at the root by underground rhizomes to form a colony - vigorous and good for filling ground in a relaxed border, but it will spread where it is happy, so give it room to run or lift and divide it to keep it in check. The dense clusters of open bells are excellent for bees, especially bumblebees. POWO (Kew) and Wikipedia record no edible use, so treat it as an ornamental only.

Care tips

•

Give it room to run: it spreads steadily by underground rhizomes, so site it where a colony is welcome, or lift and divide every few years to keep it in bounds.

•

Cut the spent flowering stems back after the first flush of clustered heads - it tidies the clump and often coaxes a second, lighter show into late summer.

•

Plant it in full sun or light shade in ordinary, moisture-retentive but well-drained soil; it is unfussy and tolerates alkaline, chalky ground, reflecting its wild grassland habitat.

Lifecycle

Planting

Plant in spring or autumn in ordinary, moisture-retentive but well-drained soil in full sun or light shade, spacing about 15 inches apart. It is unfussy and tolerates a wide range of soils, including the chalky, alkaline ground of its wild grassland habitat; give it room to spread, since it runs at the root.

Transplanting

Move young plants or rooted divisions in spring or early autumn, lifting a generous root ball with a section of the spreading rhizome; established colonies shift easily and divide readily.

Early growth

Keep the soil evenly moist while the basal clump establishes. Expect mainly leafy growth the first season with light bloom; the full flush of clustered heads comes once the plant has bulked up and the rhizomes have begun to run.

Maturity

Mature plants reach about 12 to 24 inches tall in flower and spread steadily by underground rhizomes to 12 to 24 inches or more. Cut spent flowering stems back after the first flush to tidy the clump and encourage a second show; lift and divide every few years to renew vigour and to keep the colony from outrunning its space.

Propagation

Easiest by spring or autumn division of the spreading clumps - each rhizome section with roots grows away quickly - or from seed for the species; named colour forms such as "Superba" are best divided to keep them true.

Similar plants

Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.

Geranium macrorrhizum

Bigroot geranium

A vigorous, semi-evergreen, clump- and colony-forming hardy geranium grown as one of the best groundcovers for dry shade under trees and shrubs. Its soft, deeply lobed, strongly aromatic leaves form a dense, weed-smothering carpet, many of them flushing red and bronze in autumn, and above the foliage rise loose clusters of magenta-pink (or white) flowers with prominent protruding stamens in late spring and early summer. It spreads steadily by thick surface rhizomes into a tough, low-maintenance, weed-proof mat that is easy to pull back and is not aggressively invasive. The aromatic foliage makes it markedly deer- and rabbit-resistant, and it is genuinely drought-tolerant once established. It is grown purely as an ornamental and is not a food plant.

Perennial

Full sun / Part shade

A tough, aromatic garden hybrid (Nepeta racemosa x N. nepetella) that forms a low, spreading mound of scalloped gray-green leaves topped by raceme-like spikes of two-lipped lavender-blue flowers from late spring into fall. Sterile and clump-forming rather than weedy, it shrugs off heat, drought, and deer, draws bees all season, and is mildly attractive to cats - a workhorse for border fronts, edging, and dry sunny sites.

Perennial

Full sun / Part shade

A low, clump-forming native woodland violet of eastern North America, grown for its early spring blue-to-purple flowers with conspicuous white throats held over glossy, heart-shaped leaves. It does not run, but self-seeds freely - to the point of being weedy in rich, moist ground. A larval host for fritillary butterflies and a nectar source for early bees and butterflies; the leaves are high in vitamins A and C.

Perennial

Full sun / Part sun / Part shade

The true wild primrose of European woodland and hedge banks - low rosettes of crinkled, tongue-shaped leaves throwing up many single, pale soft-yellow flowers with a deeper yellow eye, one per slender stem, among the very first blooms of the year in late winter and early spring. This is the genuine species (gentle pale yellow), NOT the loud multi-coloured Polyanthus and Primula hybrids sold as winter bedding. POWO (Kew) places it native across western and southern Europe, North Africa, and southwest Asia; RHS holds it with the Award of Garden Merit and rates it fully hardy. Its flowers and young leaves are edible, and it is a crucial early nectar source for the first bees and butterflies.

Perennial

Part shade / Full sun

Among the very first flowers of the year, the common snowdrop pushes up through cold soil in late winter to open a single nodding white bell on each short stem, the inner segments marked with a neat green tip. A small late-winter bulb of mainland European woodland and grass, it is the classic naturalising snowdrop - left undisturbed, a few bulbs slowly spread into the drifts and sheets that carpet a winter garden. Honest cautions: all parts are mildly toxic if eaten (it contains galanthamine and lectins), and it is best moved and divided 'in the green' - in leaf, just after flowering - rather than bought and planted as a dry bulb.

Perennial

Part shade / Full sun

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.

Perennial

Full sun / Part shade

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?

- Which source-backed facts would you cite in a lesson handout?

Use the Sources & citations section below for page citation styles and the field-level source list.

Sources & citations

Cite this page

For lesson plans, articles, or research that uses this page. Use the source cards below to explore the references that informed this record.

Plotwright. (2026, May 17). Clustered bellflower (Campanula glomerata). Retrieved 2026, August 20, from https://plotwright.com/plants/campanula-glomerata

Sources used for this record

This record is compiled from the sources below.

Plants of the World Online (POWO)

Botanical research database

Open source

Source guide

RHS Find a Plant

Botanical research database

Open source

Source guide

GBIF

Botanical research database