With their colorful blooms, Bellflowers (Campanula) are invaluable for summer gardens. Here’s how to plant and care for them.
With their beautiful white flowers, or blue and violet blooms in every shade imaginable, Bellflowers (Campanula) are invaluable for summer gardens. The genus, which belongs to the Bellflower (Campanulaceae) family, includes over 300 species. Most of them are deciduous shrubs, although some are evergreen. A few species are cultivated as annuals or perennials. They occur naturally in the most varied living spaces in the northern hemisphere. Many originate from the Mediterranean, Balkan peninsula and Caucuses, however, some also come from East Asia, North America, Iran and the Himalayas.
They are as varied in occurrence in nature as the location requirements are for the different species. As Bellflowers will grow in meadows as well as mountain ranges and high mountains. There is also a suitable species for almost every garden location: from flower beds to the edge of woodlands, free areas to rock steppes, rocky areas, rock crevices and wall copings.
Appearance and Growth
The various species of Bellflowers also differ significantly in regard to their size and growth behavior. While the smallest species, such as the fairy’s thimble (Campanula cochleariifolia) or the Tussock Bellflower (Campanula carpatica) have compact growth and form low cushions and can also only grow 3.94 inches tall, the large species such as the Milky Bellflower (Campanula lactiflora) can grow to up to 7 feet tall and have an elegant, upright growth.
The Bellflowers can be easily recognized by their bell, tube or star shaped flowers which open between June and September, depending on the species and variety. These flowers are also what give the Bellflowers their name, as Campanula is Latin for ‘tiny bell’. The majority of Bellflowers bloom in violet or blue. The color spectrum here ranges from pale sky blue to deep violet. There are also numerous white blooming varieties, such as the dwarf Bellflower ‘Bavaria white’ or the clustered bellflower ‘Alba’. However, it is not only the flower colors and shapes which vary. The configuration of the individual flowers also varies from species to species. Sometimes they stand in panicles, sometimes in clusters but often also individually. The leaves are undivided but can often be cordate or serrated.
Location and Soil
There is one thing most Bellflowers have in common: They prefer a sunny to semi-shady location, essentially thrive in any nutrient-rich, permeable soil and react quite sensitively to wet conditions.
The low, cushion-forming species prefer a permeable soil. To create the perfect location, the soil can be supplemented with sand before planting. In addition, Bellflowers should be planted from spring to fall.
After flowering, or - for species which should self-sow wild - in the spring, bellflowers are cut down to approx. the height of a hand’s width from the ground. Most species and varieties are divided in the spring or fall. This should be done approx. every 6 to 10 years, when the plants begin to grow bare. Both of the species used as houseplants grow very quickly and therefore require regular watering and fertilizing. The earth in the pot should always be moist. They should be fertilized once a week between April and August.
Overwintering or Winter Protection
Species which are used as houseplants can go out on the balcony in the summer but they should be moved back indoors at the start of September. Here, they should first be cut back and then only given a little water and no fertilizer during the winter months. The temperature in their winter residence should not exceed 50 degrees Fahrenheit, if possible.
Bellflowers can be used in many ways in the garden, depending on their location requirements. The low, cushion and mat forming species add color to rock crevices, wall caps and rock gardens. They work well with low Yarrow (Achillea), Thyme (Thymus) or Baby’s Breath (Gypsophila). In sunny, mixed shrub borders, the higher species such as the peach-leaved bellflower or the clustered Bellflower look great next to tall Yarrow, Evening Primrose (Oenothera), Leucanthemum or Culver’s root (Veronicastrum). Their romantic flower shape also makes then a popular companion for Roses. False Spirea (Astilbe), Foxglove (Digitalis) or Goat’s Beard (Aruncus) are suitable partners in shady flower beds.
Some species of Bellflower can even be used as houseplants. Two species which originate from Italy are popular here, although these are a little frost-sensitive: the Italian Bellflower (Campanula fragilis) and Falling Stars (Campanula isophylla). Both form their flowers on longer shoots which hang beautifully over the edge of the plant pot. These are already available in March. However, in summer, these species can also be planted in balcony boxes, provided they are overwintered indoors. The winter-hardy Dalmatian bellflower is often offered as a house or balcony plant.
Important Species and Varieties
The large genus of Bellflowers is often sub-divided into several groups - based on how they can be used in the garden. The first group includes the mid-sized to large species which are suitable for planting in flower beds, such as the Cluster Bellflower (Campanula glomerata), the Nettle-leaved Bellflower (Campanula trachelium), the wide-leaved Giant Bellflower (Campanula latifolia), Canterbury Bells (Campanula medium) or the Peach-leaved Bellflower (Campanula persicifolia). There are numerous commercially available species of the latter in particular, which can have single and double-flowers. Many of the taller species are also suitable as cut flowers. With their 7.87 to 20 inch tall stem, the Harebell (Campanula rotundifolia) is mid-sized and thrives both in wild flower meadows and also in natural rock gardens.
The second group includes the lower-growing species, which prefer drier, meagre locations and are therefore good for rock gardens, dry stone walls and troughs. These include, for example, the Dwarf Bellflower, the Tussock Bellflower, the Dalmatian Bellflower (Campanula portenschlagiana) and the Trailing Bellflower (Campanula poscharskyana). However, this genus also has numerous other species on hand for fans which do not fit into either of the two groups, such as the biennial Yellow Bellflower (Campanula thyrsoides) or numerous other varieties of the dotted Bellflower (Campanula Punctata-Hybriden) such as ‘Beetroot’ or ‘Sarastro’.
As diverse as the genus is, so too are the propagation options for Bellflowers. Some can be propagated through rooted leaf rosettes, others through basal cuttings. However, most varieties are divided or can be grown from seeds. Some species also propagate through self-sowing.
Diseases and Pests
Bellflowers are only occasionally infested with gray mold or downy mildew. Rust is the biggest threat to Bellflowers. This fungal disease occurs in three forms on Bellflowers. While Coleosporium tussilaginis occurs primarily in cluster Bellflowers and the peach-leaved Bellflowers, the latter can be infested by the specific Campanula rust (Puccinia campanulae). The rust fungus Aecidium campanulastri is also a frequent occurrence on Bellflowers. The Tussock Bellflower in particular frequently suffers from being eaten by snails.
Frequently Asked Questions
Where do Bellflowers get their name?
The name Bellflower comes from their flower shape: Campanula means ‘bell’ or ‘little bell’. The botanical name was given to the Bellflowers by the Swedish botanist and nature researcher Carl von Linné.
How much sun do Bellflowers need?
Bellflowers thrive both in a sunny and an off-sunny or semi-shady location.
How often should Bellflowers be watered?
Bellflowers are extremely uncomplicated where watering is concerned. However, during longer dry periods they should be watered before they get too dry. Even freshly planted specimens and Bellflowers kept as houseplants should be regularly watered.
How long do Bellflowers bloom?
Bellflowers bloom between June and September, depending on the species and variety.