Canterbury bells' Latin name is campanula, but they are also known simply as bellflower. According to Greenhouse Product News, there are more than 300 species of Canterbury bells, which include annual, biennial and perennial varieties. Knowing which type of Canterbury bell is in your garden will help with growing and winterizing these flowers.
Plant the Canterbury bell according to its type to help the flower survive winter. There are three broad groups of campanula, each requiring different growing conditions. Border plants require well-drained, rich soil. Rock garden species require moist, fast-draining soil. The alpine variety that doesn't do well in wet winter conditions needs a bed with sand or grit added to the soil.
Prune the flowers stems as they fade; cut these stems completely to the ground. Insert plant markers into the soil near the Canterbury bells after pruning. In some areas these flowers are evergreen, but in other areas they will lose their foliage in the winter. Using a plant marker prevents harming the plants by accidentally digging them up in the spring.
Cover the flower bed with a 2-inch layer of mulch or decaying leaves. Mulch or decaying leaves not only retains soil moisture and warmth, but they also provide nutrients to the soil.