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Clustered bellflower

Clustered bellflower

Campanula glomerata · Campanulaceae

🌿 Common garden plant

📷 Dag Lindgren · CC BY-SA 3.0

ExposureFull sun
WateringModerate watering
Hardiness~-20 °C
Mature size~50 cm
CareEasy
Bloomingfrom May to July
🐝 Bee-friendly

The gardener's calendar

The right move for September

Ideal time to plant clustered bellflower: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.

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ID card

Family
Campanulaceae
Type
Perennial herbaceous plant
Foliage
Deciduous
Flowering
May to July
Flower color
Blue-violet, white or pink depending on varieties
Adult size
40 to 50 cm in height
Hardiness
Very hardy (down to -15°C)
Origin
Central and southern Europe

✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.

Expert tips

✓ Taxonomy verified

The key tip

Clustered bellflower spreads quickly via rhizomes: divide it every 2-3 years in spring to prevent it from choking itself out. Deadhead spent flowers to extend blooming through July.

The common mistake

Letting it spread without division: it becomes a scraggly tangle that flowers poorly in the center.

The pro's trick

Pinch back young stems in May to boost flower count on more compact plants—an easy trick to test on half your bed first.

Care

Exposure

Clustered bellflower prefers full sun for generous flowering, but tolerates partial shade. It adapts well to mountain gardens or cool regions where it will benefit from optimal light.

Watering

Keep the soil regularly moist without excess, especially during growth and flowering. Reduce watering in winter. Light mulching helps retain soil moisture and limit evaporation during dry periods.

Soil

Prefer well-drained, light and slightly alkaline to neutral soil. The plant fears waterlogging which causes root rot. Enrich the soil with light compost when planting.

Pruning and maintenance

Remove faded flowers regularly to prolong flowering. After flowering, cut stems back to 10 cm from the ground to encourage vigorous growth the following year. Clean up dead foliage at the end of winter.

Fertilizer

A balanced fertilizer application in spring is quite sufficient. Avoid excess nitrogen which would promote foliage at the expense of flowers. Moderate fertilizing every two months during the growing season is recommended.

Diseases and pests

Generally robust, clustered bellflower can be prone to slugs and spider mites in dry conditions. Respect spacing and ensure good air circulation to prevent fungal diseases.

Did you know?

Clustered bellflower owes its scientific name 'glomerata' to the Latin word 'glomus' meaning 'ball' or 'sphere', referring to its densely packed flowers in compact flower heads. Once used in folk medicine for its supposed calming properties, it gradually became established as a major ornamental flower in English cottage-style gardens during the 19th and 20th centuries.

Where to buy it

Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.

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Tips generated and checked by Viridia — adapt them to your local climate.