Campanula glomerata is a popular perennial that is also known as clustered bellflower. This name is due to the plant’s showy, bell-shaped flowers that appear in ball-shaped clusters at the top of the stems. Native to forests and roadsides of Europe, campanula is easy to grow and is cultivated in gardens throughout North America. It may be aggressive and it takes some extra work to keep it within it’s boundaries.
These types of campanula grow from 8 to 24 inches (20 to 61 cm) tall. The flowers are strongly scented and appear in mid-summer above the light green, oval leaves. The flowers are usually bright purple, but may be white or blue. Each flower tends to be darker toward the center, fading to a lighter shade on the outer edges.
Caring for campanula glomerata can be a lot of work, as it grows rapidly and can even become invasive. It has the potential to crowd out smaller, less hardy plants and take over a garden. Small plants can be pulled out and larger ones may be cut back to combat this problem. Removal of spent flower blossoms before they go to seed will help to keep new plants from growing. It can also be planted in a separate, small garden plot where spreading is not an issue.
Established plants are quite hardy and will grow in most areas, even those with extremely cold winters. They usually benefit from a thick layer of winter mulch to protect the roots in these areas. Campanula glomerata plants are very happy in hot climates and will tolerate periods of drought. They prefer moist, well-drained soil and full sun, but will grow in partial shade, though less flowers may be produced.
Campanula glomerata can be started easily from seed. The seeds should be just barely covered with soil and kept moist in a sunny window until they sprout, which usually takes anywhere from two to four weeks. Seedlings can be planted in the ground when they have reached 3 to 4 inches (8 to 10 cm) tall. Mature plants can also be dug up and divided in the fall to create several new plants. They should be replanted and watered well immediately after dividing.
Campanula can be kept as a potted plant if placed in an area where it will receive several hours of direct sunlight each day. The pot should have several drainage holes in the bottom to prevent soggy roots. In winter, dry indoor air can cause the campanula glomerata to wither. Placing the pot in a humid bathroom or using a humidifier can help to keep the plant healthy until it can be placed outdoors in the spring.