Campanula–commonly called bellflower–are popular perennials and biennials covered with bell-shaped flowers. Varieties include small mounded plants and tall branched plants. There are nearly 300 species of bellflower.
Campana is Latin for “bell.” Campanula flowers are usually bell-shaped but can also be a star, cup, or saucer-shaped. Each flower has five “petals” or lobes. Flowers are usually borne in clusters. Flowers come in shades of blue, lilac, violet, and white. There is a campanula suited for nearly every garden.
Campanulas range in size from 6-inch ground-covering plants to 5-foot towering plants. Campanulas form clumps or rosettes of leaves from which the upright flowering stems rise bearing smaller-stemmed leaves. Flowers can be blue, lavender, purple, and white.
Plant Campanula in full to partial shade for the longest season of blooms.
Get to know Campanula
- Plant type: Perennial, biennial, or annual
- Growing Zones and range: Zones 3 to 8 as perennials, Zones 3 to 9 as biennials and annuals
- Hardiness: Hardy to -30°F (-34°C); tolerates harsh winters and drought
- Height and width: most cultivars are 5 to 36 inches (12-91cm) tall and wide, some grow to 6 feet (1.8m) tall
- Foliage: Clump-forming, rosettes or tufts of bright-green, heart-shaped leaves from which flowering stems arise
- Flowers: Bell-shaped, cupped, lavender-blue flowers; some cultivars are purple and white
- Flower colors: Predominantly blue, also pink, rose, lavender, and white
- Bloom time: Midsummer to fall depending on the species
- Uses: Fill space in perennial beds, rock gardens, groundcover, rock walls, containers, hanging baskets
- Garden companions: Siberian iris, leopard’s bane, ferns
- Common name: Bellflower
- Botanical name: Campanula spp.
- Family: Campanulaceae
- Origin: Found widely in temperate zones of Nothern Hemisphere
Where to plant Campanula
- Plant Campanula in full or partial shade in Zones 4 to 5; plant in partial shade in Zones 6 to 9.
- Grow Campanula in humus-rich, moisture-retentive, well-drained soil; will grow in average soil. Campanula can tolerate alkaline soil.
- Campanula grows best in a soil pH of 5.5 to 7.
Campanula uses and companions
- Plant Campanulas in beds and borders.
- Use Campanulas to fill space in perennial beds, rock gardens, groundcover, rock walls, containers, hanging baskets
- They will spill from hanging baskets and pots.
- Plant Campanulas with Shirley Poppies.
- Campanulas make long-lasting cut flowers.
- Good garden companions for Campanula include Alchemilla mollis, Aquilegia, Heuchera, Hosta, Siberian Iris, Thalictrum.
When to plant Campanula
- Set established plants in the garden in spring or fall.
- Sow seeds indoors in early spring for annuals and perennials or early fall for perennials and biennials.
- Sow seed outdoors in early spring or early fall.
- Set plants started indoors when plants have four or five true leaves—transplant perennials in late spring or fall. Biennials may be set out from late summer to fall, until two weeks before the first hard freeze.
Planting and spacing Campanula
- Sow seeds indoors in premoistened soil in a flat or six-pack; barely cover with soil. Keep seeds warm at 70°F (21°C) until seeds germinate in about two weeks.
- Direct seed-only species that thrive in your region.
- Set container-grown plants outdoors in spring after the last frost or in fall. Harden off plants before putting them in the garden.
- Space Campanula 8 to 10 inches (20-25cm) apart.
How to water and feed Campanula
- Keep the soil evenly moist. Campanula is drought tolerant but it is best to water in dry weather.
- Fertilize Campanula lightly with an all-purpose fertilizer at planting time.
- Fertilize with fish emulsion every two to three weeks during the growing season.
Campanula care
- Mulch around plants to keep the soil cool and moist.
- Cut back flowering stems after blossoms fade.
- Protect pants in winter by spreading 5 inches (12cm) of chopped leaves or straw.
Growing Campanula as a houseplant
- Campanula isophylla is often grown as a houseplant.
- Grow Campanula in a cool room with average or high humidity and direct light.
- The growing medium should be rich, well-drained, and evenly moist.
- Fertilize Campanula monthly from spring through fall.
- Pinch out growing tips if plants become leggy.
Campanula pests and diseases
- Exclude slugs with barrier strips of diatomaceous earth; bait them with shallow pans of beer set flush with the soil surface.
- Aphids may attack Campanula.
- Campanula is susceptible to botrytis blight, leaf spots, powdery mildew, and root and stem rot.
Campanula propagation
- Divide established overgrown clumps to keep the plants vigorous. Dig and divide clumps when they become crowded.
- Divide in fall or early spring.
- Sow seed indoors; leave seed uncovered as light promotes germination.
- Seeds germinate in 20 to 30 days at 65° to 70°F (18°-21°C).
- Plants grown from seed sown indoors in late fall will flower early the following summer but they must get artificial light through the winter during short days.
- Campanula takes 6 months to flower from seed; purchased transplants will provide the earliest blooms.
Campanula varieties to grow
- Campanula carpatica is known as Carpathian bellflower; it forms a mound of blue, violet, and white flowers in summer. Cultivars include ‘Blue Clips’, ‘White Clips’, ‘Bressingham White’, and ‘Jewel’.
- C. glomerata, clustered Bellflower, showy perennial, spikes topped by clusters of vibrant purple blossoms.
- C. isophylla, Italian bellflower. Trailing plant for cool regions; use as a groundcover or in hanging baskets.
- C. medium, Canterbury bells, showy biennial grow to 4 feet (1.2m) tall.
- C. persicifolia grows 2 to 3 feet (.6-.9m) tall and is quite heat tolerant.
- C. medium is an old-fashioned biennial that can grow to 4 feet (1.2m) tall. It blooms the second year after planting.
- C. portneschlagiana, Dalmatian bellflower, is trailing.
- C. lactiflora can send flowering stems to 5 feet (1.5m) high with domed clusters of blooms.
Campanula carpatica — Carpathian bellflower
Carpathian bellflower is a long-blooming bellflower with triangular, 2-inch-long, bright green, toothed leaves. This plant forms tidy, low mounds from spring through fall and blooms from early summer to midsummer, and sporadically through fall. The plant sends up multiple stems topped with solitary; 2-inch-wide, bowl-shaped blue and white flowers. The plant readily spreads into lovely clumps.
- Size: 9 inches to 1 foot tall; 1 foot wide.
- Light: Full sun to part shade.
- Soil and moisture: Well-drained, average to sandy soil; keep the soil moist but never wet.
- Planting and propagation: Plant container-grown plants in spring, spacing 1 foot apart. Divide in spring, every three years.
- Special care: Deadhead to prolong blooming. Keep roots cool with summer mulch. May self-sow, but rarely weedy.
- Pests and diseases: Short-lived in poorly drained soil or drought conditions. Snails and slugs may be troublesome.
- Climate: Zones 3-8.
- Cultivars: ‘Alba,’ white; ‘Blue Clips,’ blue, 6 to 8 inches tall; ‘White Clips,’ white, 6 to 8 inches tall; ‘Wedgewood Blue,’ sky-blue, 6 inches tall, ‘Wedgewood White,’ white, 6 inches tall; ‘China Doll,’ plate-shaped, pale blue flowers.
- Garden use: Excellent in the foreground of the border, as edging along a walkway, or in a rock garden.
Campanula garganica — Gargano bellflower
Gargano bellflower is a ground-covering plant with bright green, kidney-shaped, 1-inch-long basal leaves and ivy-shaped stem leaves. This trailing plant spreads aggressively to form mats of evergreen foliage. Gargano bellflower blooms for several weeks in late spring and early summer, and sporadically through fall. It bears clusters of pale blue to violet, star-shaped, upward-facing flowers with white centers that nearly obscure the trailing stems and leaves.
- Size: 5 to 6 inches tall; spreads into 10-inch to 1-foot-wide clumps.
- Light: Full sun to light shade.
- Soil and moisture: Average to fertile, well-drained, neutral to alkaline soil; keep moist but not soggy.
- Planting and propagation: Plant container-grown plants in spring, spacing 1 foot apart. Divide every few years in the fall.
- Special care: May be aggressive, divide frequently to control spread.
- Pests and diseases: Snails and slugs may be troublesome.
- Climate: Zones 6-8.
- Cultivars and similar species: Sometimes listed as C. elatines var. garganica, C. g. birsuta covered with fine hairs, dusky blue flowers, and gray-green leaves.
- Garden use: Makes good ground cover in a rock garden or mixed border.
Campanula glomerata — clustered bellflower
Clustered Bellflower blooms profusely from early summer to midsummer. The tall, stiff stems of this upright bellflower hold dense clusters of 1-inch, purple or violet, bell-shaped flowers with pointed petals in the leaf nodes and at the stem tips. The leaves are spear-shaped and hairy. This plant spreads rapidly to form open clumps.
- Size: 1 to 3 feet tall; 1 ½ feet wide.
- Light: Full sun in the North; part shade in the South.
- Soil and moisture: Humus-rich, well-drained neutral to alkaline soil; keep the soil moist but not soggy.
- Planting and propagation: Plant bare-root or container-grown plants in spring, spacing 1 ½ feet apart. Divide every three years.
- Special care: Can be invasive, divide every few years to control. Cut back flower stalks after flowering for possible repeat performance. Needs no staking.
- Pests and diseases: Snails and slugs may be troublesome.
- Climate: Zones 3-8.
- Cultivars: ‘Joan Elliott,’ dark violet, early flowering. 1 ½ feet tall; ‘Superba,’ violet-blue, 2 to 2 ½ feet tall, invasive, heat tolerant, ‘Alba,’ white, 2 feet tall: C. g. acaulis, light violet-blue, 3 to 5 inches tall, dwarf variety.
- Garden use: Plant in groups in informal gardens for beautiful early summer blue flowers. Combines well with pink and rose.
Campanula lactiflora — milky bellflower
Milky bellflower grows as a tall, loose bush with slender gray-green leaves topped with large, panicles of numerous, 1-inch-long, bell-shaped, milky blue to deep blue flowers with white centers. Flowers appear in midsummer lasting for several weeks. The plant reblooms readily if stems are cut back after the first flush. The pale blue flowers look especially lovely when backlit by the sun or viewed in the moonlight.
- Size: 3 to 5 feet tall; 3 feet wide.
- Light: Full sun to part shade.
- Soil and moisture: Humus-rich, well-drained soil; even moisture.
- Planting and propagation: Plant container-grown plants in spring, spacing 3 feet apart. Take cuttings in spring. Resents division and transplanting.
- Special care: After flowers fade, cut back stems to just below the lowest flowers to encourage reblooming. Self-sows to the point of weediness if not deadheaded. Pinch back stems when 6 inches tall to increase bushiness and stem strength. Requires staking to prevent leaning toward the sun and flopping on nearby plants.
- Pests and diseases: Snails and slugs may be troublesome.
- Climate: Zones 5-7.
- Cultivars: C. i. alba, white, 3 to 4 feet tall; ‘Loddon Anna,’ pale pink, 4 feet tall; ‘Pouffe,’ pale, blue, 1 ½ feet tall, no staking.
- Garden use: Graceful, long-blooming plant for informal and naturalistic gardens.
Campanula medium — Canterbury bells
Campanula medium is a biennial commonly grown as an annual., Canterbury bells can be sown early indoors to encourage flowering in midsummer of the same year (thus the plant is treated as an annual). Some early cultivars are classified as true annuals. The large blue, lilac, pink, or white bell-shaped flowers pack tall stems above a basal rosette of wavy-edged, slightly hairy leaves. Semidouble and double-blossomed cultivars are available.
- Size: 1 to 4 feet tall; half as wide.
- Light: Full sun; light shade where summers are hot.
- Soil and moisture: Rich, well-drained soil; even, plentiful moisture.
- Planting and propagation: Sow indoors, uncovered, at 64° to 70°F, six to eight weeks before late-spring transplanting, or use nursery starts. May also be sown outdoors in midsummer for bloom the following spring.
- Special care: Mulch late-sown seedlings, or overwinter in cold frame. Apply summer mulch to cool roots. Stake tall form.
- Pest and diseases: Leaf spot, powdery mildew, stem rot, crown rot, aphids, and slugs can be troublesome.
- Climate: Grow as hardy, cool-season annual or biennial in Zones 2-11.
- Cultivars and similar species: ‘Cup and Saucer,’ mixed colors, semidouble, 2 ½ feet tall; Dwarf bedding Mixture,’ 1 ¼ to 1 ½ feet tall; ‘Russian Pink,’n1 ¼ feet tall, true annual. The related C. Pyramidalis reaches 4 feet tall, and has smaller flowers.
- Garden use: Good choice for borders and cutting beds. Use dwarf in containers and rock gardens.
Campanula persicifolia — peach-leaf bellflower
Peach-leaf bellflower bears spires of bell to saucer-shaped, 1 ½-inch flowers on tall, straight stems. Flowers open from the top of the stalk downward, beginning in July and continuing through August if cut back. The clumps of evergreen, rounded basal leaves grow larger every year but are not invasive. Narrow with rounded teeth, the leathery leaves lining the flower stems don´t look like peach leaves despite its name.
- Size: 1 to 3 tall; 2 feet wide.
- Light: Full sun to light shade.
- Soil and moisture: Humus-rich, well-drained soil; even moisture.
- Planting and propagation: Plant container-grown plants in spring, spacing 2 feet apart. Divide after flowering every three years.
- Special care: Self-sows. Reblooms after faded flowering stalks are cut back to several inches above the basal mat of foliage.
- Pest and disease: Snails and slugs may be troublesome.
- Climate: Best in Zone 3-6; short-lived in Zones 7-8.
- Cultivars: ‘Telham Beauty,’ pale china blue, 3 to 4 feet tall;’ Alba’, white, 25 feet tall;’ Grandiflora Blue,’ large sky-blue flowers, 2 ½ feet tall; ‘Blue Gardenia,’ double, deep silvery blue, 3 feet tall; ‘Coerulea,’ bright blue, 3 feet tall.
- Garden use: Plant in large groups for excellent vertical effect in formal and informal borders. Long-lasting cut flower.
Campanula portenschlagiana — Dalmatian bellflower
Dalmatian bellflower is a mat-forming, blue-flowered plant that is best when cascading over a wall or spilling around boulders in a rock garden. It is equally attractive beneath shrubs and taller perennials. The 1-inch-wide, upward-facing bell-shaped flowers form an intense lavender-blue blanket that conceals the evergreen foliage for three or four weeks in late spring and early summer. Flowers may rebloom sporadically through summer. Long-stalked, 2-inch-long, heart-shaped to triangular leaves with jagged teeth from a central rosette from which long trailing stems with smaller leaves reach out in all directions. Flowering branches form along these runners.
- Size: 4 to 6 inches tall; spreads to 2 feet or more.
- Light: Full sun to light shade.
- Soil and moisture: Average to humus-rich, moist, well-drained soil; keep moist but never wet or soggy.
- Planting and propagation: Plant container-grown plants in spring, spacing 1 foot apart. Take cuttings in summer. Divide every three years.
- Special care: Must have excellent drainage.
- Pest and diseases: Snails and slugs are sometimes troublesome.
- Climate: Zones 4-8; grows better in the South than other bellflowers.
- Cultivar and similar species: ‘Reshole’, dark violet. C poscharskyana (Serbian bellflower); similar spreading habit but less invasive, blooms in mid-spring and sporadically through fall, flowers upward-facing flat stars, leaves smaller on shorter stems and more pointed tips, drought tolerant; C. palba, white flowers, Zone 3-7.
- Grden use: Best in a rock garden, over a wall, naturalistic garden, and mixed border. Use as edging along walks or in informal borders.
Campanula frequently asked questions
Q: Is the plant called star-of-Bethlehem the same Campanula that grows in the garden?
A: It’s not likely. Star-of-Bethlehem or Italian bellflower is Campanula isophylla which is often sold as a house plant in nurseries and by mail order. This is a trailing plant with beautiful gray-green foliage and a profusion of small star-shaped flowers from summer to late winter. Commonly grown outdoors are Carpathian bellflower (C. carpatica) and C. persicifolia.
Q: How can star-of-Bethlehem be grown in the house?
A: Grow star-of-Bethlehem (Italian bellflower) in sandy soil that has humus added. Place it in a sunny window in winter and light shade in summer. Keep the plant moderately moist in winter; water freely in summer. Feed the plant with a dilute solution of all-purpose indoor plant food when in growth. Propagate by cuttings in spring. Italian bellflower is one of the best of all summer-flowering trailing plants.
