Campanula, also known as bell flower, is a genus of flowering plants consisting of over 300 different species, resulting in a wide variety of colours, growth habits and sizes. Campanula can bloom between late spring and early fall, producing blue, lavender, pink or white flowers. They can grow to a mature height between 4 inches and 4 feet, depending on the species. Campanula is easy to grow in most temperate climates, especially in hardiness zones 3 through 8.
Sow campanula seeds indoors about five weeks prior to the final frost of winter. Use a well-drained and fertile soil. Transplant outdoors after the campanula has sprouted and all danger of frost has passed. Allow 12 to 18 inches of space between each campanula plant. Ensure the planting location receives full morning sun and partial afternoon shade.
Spread a 2-inch layer of mulch around the newly planted campanula. Start the band about 3 inches from the base of the plant to allow room for growth. Refresh the mulch as needed, especially during the winter when the soil needs insulation to prevent heaving.
Water campanula plants deeply once per week during spring, summer and fall. Reduce watering to once every two weeks during winter. Do not water on weeks that receive heavy rainfall or the plant can become waterlogged and rot.
Feed campanula twice per year, once in late winter and again in early spring. Use a balanced 10-10-10 NPK fertiliser according to the manufacturer's instructions. Water both before and after application to prevent root burn.
Remove dead or faded flowers from stems only when all of the flowers on that stem have faded. Pinch them off as close to the stem as possible, and new blossoms will form within a few days. No further pruning of campanula plants is required.
Shredded cedar mulch is ideal as it is resistant to erosion and is a mild pest repellent. Pruning flowers prior to the fading of all of the flowers on the stem will cause campanula to focus all nutrients on turning the remaining flower to seed instead of producing more blossoms.