Canterbury Bells Plant Profile

Biennial Best Grown From Seed

Purple Canterbury bells

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Canterbury bells is a biennial that has been popular for many years in European and North American landscapes. It is a medium-sized specimen with an upright plant form. Its best feature is the numerous, bell-shaped flowers it produces.

  • Botanical Name: Campanula medium
  • Common Name: Canterbury bells, cups and saucers
  • Plant Type: Biennial
  • Mature Size: 20 to 26 inches tall and 12 to 18 inches wide
  • Sun ExposureFull sun to partial shade
  • Soil Type: Rich, well-drained, and kept evenly moist
  • Soil pH: Neutral to slightly acidic or slightly alkaline
  • Bloom Time: Early summer, on average
  • Flower Color: pink, white, purple, and blue
  • Hardiness Zones: 5 to 8
  • Native Area: Southern Europe
canterbury bells from the side
Image Source / Getty Images 

How to Grow Canterbury Bells

Indigenous to the Mediterranean climate of southern Europe, Canterbury bells does not do well in the humid climate of regions such as the southeastern United States, but it performs well in all but the coldest portions of the northern United States.

As a biennial, Canterbury bells takes two years to bloom, after which time it will die. The best way to grow a crop of them is to start them by seed. Here's how:

  • Sow the seed in a tray filled with potting soil in late winter.
  • Sprinkle a light covering of vermiculite over the seeds.
  • Using a spray bottle full of water, spray the vermiculite lightly to keep it evenly moist but not soggy.
  • Room temperature should be 65 to 70 degrees Fahrenheit.
  • When the seedlings emerge (three to four weeks), put the tray in a sunny window and keep the soil evenly moist.
  • In mid-spring, begin hardening off the seedlings.
  • Transplant the seedlings into the spot in the garden that you have selected for them once danger of frost has passed.
  • You will have only vegetation the first year. The next year, you will have flowers.

Common pests and diseases include: Aphids, mites, slugs, snails, powdery mildew, and rust. Given the height of the plant, it is helpful to provide support by staking it.

Light

Although it will survive in partial shade, Canterbury bells flowers better when planted in full sun.

Soil

Mix compost into the ground where you plant it not only to increase fertility but also to improve soil drainage.

Water

Water regularly during the growing season, the goal being to keep the soil consistently moist but not soggy.

Fertilizer

Fertilize in late spring with a balanced fertilizer. Hose down the soil thoroughly afterward so that the fertilizer goes down to the roots.

The Bellflower Family

Canterbury bells is a member of the bellflower family, so-called for the bell shape of the flowers. Members of the family typically have "bell" in their common names, such as harebell (Campanula rotundifolia).

The Campanula genus is diverse, having not only upright plants such as Canterbury bells but also plants that behave more like ground covers. An example of the latter is Dalmatian bellflower (Campanula portenschlagiana). Such shorter plants are well suited for use in rock gardens.

North America gardeners interested in growing native plant gardens can use a Campanula native to their region. It is aptly named Campanula americana (the common name is tall bellflower). This herbaceous perennial reaches 3 to 6 feet in height and 1 to 2 feet in width and has blue flowers. Grow it in zones 4 to 7 in full sun to partial shade.

Varieties of Canterbury Bells

Canterbury bells comes in a number of cultivars and seed mixes, including:

  • Campanula medium var. calycanthema alba: 24 to 36 inches tall; white flowers
  • Campanula medium Bells of Holland: 18 inches tall; pink, purple, or white flowers
  • Campanula medium Champion Pink: 2 feet tall; pink flowers
  • Campanula medium Dwarf Bella Mix: 14 inches tall; blue, lilac, pink, or white flowers
  • Campanula medium Double Melton Mix: 3 feet tall; flowers dark pink, light pink, or purple; double blooms

Landscape Uses for Canterbury Bells

Canterbury bells is not known to be poisonous, either to people or to pets. It does well in containers. These facts make it a great choice when you need a plant to grow in an urn or whiskey barrel on a deck or a patio where kids will be playing or where pets will be basking in the sun.

More commonly, Canterbury bells is grown in flower beds, where its medium height makes it just about right for the second row in a bed of three rows, staggered according to height. It is also wonderful massed together in border plantings. It is a classic cottage garden plant.