The Campanula flower is a group of endearing plants offering something to everyone, from the:
- Beginning gardener
- Rock-garden specialist
- Houseplant hobbyist
Among the most rewarding characteristics of Campanula varieties are the ones producing myriads of starry saucer-flowers in celestial white flowers or campanula-blue flowers tumbling from pots, hanging baskets, and containers.
From the family Campanulaceae, the Campanulas go by a variety of common names:
- Canterbury Bells
- Star of Bethlehem
- Falling Star
- Serbian bellflower
The strong, heavily flowered stems are excellent as cut flowers. The compact plants produce abundant flowers in clear colors in shades of blue, purple, pink or white bell flowers.
The Campanula genus numbers over 250+ annual, biennial and perennial species.
Hardy Garden Perennial Plants
These are mainly hardy garden perennials with branched and trailing stems, but some are grown in indoor pots and baskets because they come into flower in late summer, fall, and early winter, when they might be killed back outdoors.
Recommended for USDA hardiness zones 4 – 10 and grow as natives in many regions around the globe where the they enjoy cool nights.
These flowers were a frequent gardening subject, and spectacular as a common sight in old country kitchens, where the temperature seldom soared above 70° degrees Fahrenheit except on weekly baking day, and pump water ran icy into the sink.
Since then, central heating has made us more comfortable but banished garden plants like the Bellflower flower to a cool porch or greenhouse.
But since they are so utterly charming, they’re well worth any effort to provide good growing conditions.
Who doesn’t want flower-filled baskets to bring into the living-room window or flower-covered pots to use as centerpieces or in table-top compositions?
Flower Care – Temperature, Light, Water & Soil
The best growth for the bellflower plant is produced in temperatures around 65° degrees Fahrenheit. Full sun produces the most bountiful flower display – with some partial shade against noonday heat in tropical areas.
Caring for white Campanula flowers consists of the need for constant moisture during the active growing season. Select a rich, light well-drained soil type mixture. Add lime if the soil is acid.
Although the flowers it produces seldom stops growing entirely, they do rest after the flowering period. At that time, cut off old flowering branches at the base, to make room for new shoots already poking up their heads.
For a month or two, keep the pot or basket in a cool, sunny spot (full sun if possible) with less water than usual. In January or February, repot – or replant with fresh soil in the old pot – and resume regular watering and fertilizing (liquid feeding is good).
From then until early summer, pinch out branch tips to encourage fuller growth and more flowering stems.
Increase fertilizer rations during the bloom time, and keep faded blooms picked off so it won’t use its energy to set seeds.
Mature plants are increased by division during or immediately after semi-dormancy. Basal stem cuttings of semi-hardened wood will root with less risk than soft, new growing tips.
Campanula Pests and Diseases
Purple Campanula faces many of the usual suspect pests in the garden – Aphids, thrips, and slugs
Diseases – Crown rot, leaf spot, rust, powdery mildew, and root rot.
Species and Varieties
Among the varieties generally grown in pots or baskets many favor those with large, single star-flowers like a flattened platycodon. The doubles are fully double, like baby roses, but not nearly so pristine.
Once established they are fairly drought tolerant. Another plus is they are deer and rabbit resistant.
Campanula Carpatica – (Carpathian bellflower, harebell or tussock bluebell)
Campanula elatines – A slender, spreading plant with stems turning up at the tip. As far as I know, the single, azure-flowering species is not often available. The variety alba plena has double white flowers; fore pleno, double blue. Both flower from July through fall.
Campanula fragilis – A true trailer, flowering earlier (July-August) with cupped porcelain-blue starry platters.
Campanula glomerata – (Clustered bellflower) green, herbaceous perennial, short, pubescent simple erect stems, green ovate heart-shaped leaves, violet-blue flowers.
Campanula isophylla – Single blue star of Bethlehem. Cascades of inch-wide star flowers appear in spurts from midsummer through the holiday season.
Campanula elatines garganica – Usually flowers in June, violet-blue against fuzzy dark-green leaves.
Campanula lactiflora – (Milky bellflower)
Campanula medium – (Canterbury Bells) – large, blue, white, violet, and pink flowers bloom a long time.
Campanula muralis – (correctly Campanula portenschlagiana) Open bell-shaped flowers in late spring early summer.
Campanula persicifolia – (peach-leaved bellflower or willowleaf belIflower)
Campanula poscharskyana – Rampant and evergreen in mild climates, with showers of lavender flowers at intervals all summer.
It makes a good ground cover and looks great in rock gardens.
Neat, toothed, heart-shaped leaves are smothered by showy purple, starry flowers in early Summer. It does well in part shade or shade.
Campanula pyramidalis – (Chimney Bellflower) The latest of all the lavender-blue perennials Campanulas with its heaviest blooming period in late August and September.
Campanula rotundifolia – (Harebell) Beloved bluebell of Scotland, a well-branched trailer that dangles loose clusters of blue flowers off and on from summer into early fall.
Care Questions and Answers
Question: Last year my Canterbury Bells got off to a slow start and did not bloom this year. They are now beautiful plants. Are they likely to bloom next year or should I pull them out? – RG. Wyckoff, NY.
Answer: If your large plants go safely through the winter, they should make a fine showing next year.
Question: I planted canterbury from seed in the late spring of last year. They developed into fine healthy plants, overwintered well, and now are large healthy looking plants but have never shown any sign of blooming.
Can you tell me why? Will they overwinter another season? IK, Minnesota.
Answer: Campanula Medium is the bellflower usually called “Canterbury bells.” It is a biennial and blooms on the second year’s growth, then dies.
Apparently, your plants have not completed the cycle of growth necessary to bring them to bloom. They should persist over winter and come to bloom next year, then die.
Question: Last spring I planted Canterburybells, but they didn’t bloom. Should I have taken them up for winter? How should I care for them to produce bloom?
Answer: Canterbury bellflowers (medium) are biennials. They require two growing seasons to come into bloom. Some varieties are difficult to winter over unless stored in a cold frame.
However, most will survive the winter protected only by their own foliage or with a little coarse mulch, such as dead flower stems. The plants grown last season, by next June, should be among the showiest plants in the flower garden.
A light application of plant food when the growing season starts in early spring will produce more vigorous growth and increase the flower size.
Question: I have been told about a low-growing variety which makes a good ground cover. Can you tell me the name of the plant?
Answer: The plant in question is Campanula poscharskyana, the Poscharsky bellflower. Neat, toothed, heart-shaped leaves are smothered by showy starry, purple flowers in early Summer. It does well in part shade or shade.