Canterbury Bells (Campanula medium)

Canterbury Bells, Coventry Bells, Cup and Saucer

The flowers of canterbury bells (Campanula medium) are bell-shaped; hence, the name. It is a native Southern European plant. In floriography, a coded language communicated through flowers that dates back to Victorian times, it represents gratitude. It is one of the flowers Thomas Jefferson grew at Monticello, his homestead

I. Appearance and Characteristics 

Campanula medium, common name Canterbury bells, is an annual or biennial flowering plant of the genus Campanula, belonging to the family Campanulaceae. In floriography, it represents gratitude, or faith and constancy.

Campanula medium originates in southern Europe. It is naturalized in most European countries and in North America and it is widely cultivated for its beautiful flowers.

It grows on stony, rocky and bushy slopes, at an altitude of 0–1,500 metres (0–4,921 ft) above sea level.

Campanula medium reaches approximately 60–80 cm (24–31 in) in height. This biennial herbaceous plant forms rosettes of leaves in the first year, stems and flowers in the second one. The stem is erect, robust, reddish-brown and bristly hairy. The basal leaves are stalked and lanceolate to elliptical and 12–15 cm (5–6 in) long with serrated leaf edges. The upper leaves are smaller, lanceolate and sessile, almost embracing the stem.

The flowers are arranged in a racemose inflorescence of extremely long-lasting blooms. These attractive bell-shaped flowers are short-stalked, large and hermaphroditic, with different shades of violet-blue or rarely white. The corolla has five fused petals with lightly bent lobes (known as a coronate flower type).

The flowering period extends from May to July in the Northern Hemisphere. The flowers are either self-fertilized (autogamy) or pollinated by insects such as bees and butterflies (entomogamy). The seeds ripen from August to September and are dispersed by gravity alone (barochory).

II. How to Grow and Care

Sunlight

While the canterbury bells are at home in a cooler environment, it does still enjoy full sun or partial shade. Because of this, make sure that your plant is placed in a location that receives some shade from the hot summer sun. If the canterbury bells are situated in the direct summer sun, then the flowers may start to wilt after just a couple of days.

Temperature and Humidity

Canterbury bells do best in cool climates. If you live in an environment with hotter temperatures, provide your plant shade. Cool summer weather is ideal for Canterbury bells; temperatures over 80°F can harm your plant’s health.

Watering

The Canterbury bells require lots of water to produce its attractive, colorful, bell-like flowers. This is especially true in warm climates. If you do not water your plant regularly, then it will quickly wilt and stop producing flowers. Typically, the canterbury bells will need watering twice a week in warmer weather, but a good tip is to feel the soil before watering. It should be just slightly moist, but not water-logged or dry.

Soil

The optimum soil for your canterbury bells is fertile soil with a pH of 6-8, meaning neutral to alkaline. The soil must not dry too quickly, but should still be well-draining. Because of this, soils such as loam, sand, or clay are perfect for this plant. The canterbury bells does not like warm weather, so apply a layer of mulch to the soil in the summer. This will help to keep the soil and the roots of your plant cool and moist. The nutrients from the mulch will also encourage better growth and blooming.

Fertilizing

While it is not essential to use a fertilizer, many choose to apply an organic fertilizer to increase the quality, size and growth rate of the flowers. If you decide to use a fertilizer, apply it once or twice a month throughout the spring and the beginning of summer. Ideally, use a water-soluble fertilizer that you can apply directly to the soil. However, avoid getting any fertilizer on the canterbury bells, as this could burn the plant, and avoid nitrogen-heavy fertilizers too.

Planting Instructions

While many people choose to plant their canterbury bells in the garden, it will also happily survive when planted in an outdoor container. They are best planted in the fall, to give them enough time to establish their roots for the spring. These plants like to spread out, so be sure to plant them with enough room to do so, for example, a foot apart. Leaving this amount of space will allow for adequate air circulation around your plant, which can prevent powdery mildew.

When planting your canterbury bells, make sure that the hole is twice the size of the root ball and is about 38 cm deep, so that the tops of the roots are level with the soil surface. Then, fill the soil in and firm the top layer before watering. A good tip is to loosen the surrounding soil before planting to allow the plant to settle quicker. While the canterbury bells is occasionally kept indoors as a houseplant, this is not recommended as the lack of light and dry air can quickly damage the plant.

Pruning

The typical canterbury bells will usually grow up to 1 m and reach an ultimate spread of 1 m. They are perennial, which means that they will bloom once a year. Because of this, they do not necessarily need pruning, unless you are trying to maintain a certain shape. The canterbury bells can take up to 5 years to reach its ultimate height, which is another reason why you may not need to prune your plant for quite a few years.

If you choose to prune for shape and to encourage growth, you should do this at the end of spring, and definitely before the beginning of fall. While pruning, remove any shoots that appear weak or are growing in the wrong direction. This will encourage the plant’s energy to be diverted towards the other shoots instead. During the flowering season, some choose to remove wilted flowers, as this can prolong the flowering phase. This can be done by ‘plucking’ off the dead flowers. Deadheading flowers will also prevent this plant from self-seeding.

Propagation

The Canterbury bells can be propagated through division, planting seeds, or basal cuttings. Most choose division because the plant should be divided every five years anyway, in order to keep it growing strong and healthy, with propagating by division being easy to do. In the spring, dig up your canterbury bells and tease the roots apart. Then, gently cut the plant in half. Afterward, plant your canterbury bells in nutrient-rich soil immediately, lightly packing the soil around the plant before watering it. It is best to divide your canterbury bells on a cool day.

If you choose to plant seeds, simply sow them into nutrient-rich soil at the beginning of spring, after the last frost. Cover the ground with mulch to help the seeds germinate, and you should start to see shoots in the next 4-8 weeks. Be aware that the seeds for the canterbury bells are cold shooters, so they must be kept at a low temperature before planting to prevent them from driving out too early.

Potting and Repotting

You can plant Canterbury bells in regular potting soil without additional measures. However, you may add some sand to the mixture. Choose a pot, tub, or container with drainage holes to ensure the plant doesn’t become overly wet.

Repotting is best done in early spring, and given the height of the plant, staking is helpful for extra support.

Overwintering

It’s best to grow Canterbury bells indoors for their first year to be well-prepared for winter. You can do so by using a thick layer of mulch and planting in the spring. Water very lightly during frosts.

Pests and Diseases

Common Pests & Plant Diseases

While infestations and disease aren’t common, the plant can be affected by various insects and fungal diseases, both of which are treatable when addressed early.

Common pests and diseases affecting Canterbury bells include aphids, mites, slugs, and snails. The plant can also develop root rot, powdery mildew, and rust. Fungal diseases, such as rust, become visible as leaf lesions and open pustules that can spread to surrounding flowers. Pruning and good air circulation can help protect your Canterbury bells from disease.

Common Problems 

While Canterbury bells are relatively easy to grow and aren’t particularly susceptible to pests, they can still suffer from issues common to all bellflowers. Owners should pay attention to discoloration and overcrowded flowers.

Discoloration

Fungal diseases will cause the leaves of your Canterbury bells to become yellow or brown and are difficult to manage once the spread begins. This can be prevented by avoiding overwatering.

Overcrowding

Canterbury bells produce a large volume of flower spikes, weighing down the stem and causing the plant to collapse. You can help prevent this by staking your plant and pruning as you notice excess growth.

III. Uses and Benefits 

Canterbury bells can be used in flowerbeds and borders. This popular garden plant is the perfect solution to filling in gaps of space that appear between beds and borders, it is both prized and often used for that purpose, with the added benefit of its bright, appealing blooms. It is an excellent fit for cottage gardens as well as near-natural gardens and is often planted with the Daylily and Lamb’s Ears for their complementary blooms.

Beekeepers sometimes use the Canterbury Bell for making potentially sweet honey.

Canterbury Bells (Campanula medium) Details

Common name Canterbury Bells, Coventry Bells, Cup and Saucer
Botanical name Campanula medium
Plant type Herbaceous Perennial
Hardiness zone 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Growth rate Medium
Height 1 ft. 6 in. - 3 ft. 0 in.
Width 1 ft. 6 in. - 3 ft. 0 in.
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition High Organic Matter
Flower color Blue
Leaf color Green