The easy-care, flat growing wall bellflower transforms flower beds, rock gardens, joints and wall crowns into true carpets of flowers in summer.
Profile of wall bellflower:
Scientific name: Campanula portenschlagiana
Plant family: bellflower family (Campanulaceae)
Other names: –
Sowing time: spring to autumn
Planting time: spring to autumn
Flowering period: June to August
Location: sunny to partially shady
Soil quality: sandy to loamy, moderately nutritious to nutritious, humus rich
These information are for temperate climate!
Use in: embankments, group planting, planters, dry stone walls, area greening, flower garden, rock garden, potted garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-32 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of wall bellflower
Plant order, origin and occurrence of wall bellflower
The wall bellflower, botanically Campanula portenschlagiana, belongs to the bellflower family (Campanulaceae) and – how could it be otherwise – to the genus of bellflowers. Its natural distribution area is the mountainous regions of Dalmatia, from Croatia to Montenegro. There it grows in the mountain regions. However, it has been cultivated for a long time and all over the world, and in some places it has been released into the wild.
Characteristics of wall bellflower
The trailing shoots of wall bellflower form 10 to 15 centimeters (4 to 6 in) high cushions, which spread carpet-like by short runners, but never become annoying.
The roundish to heart-shaped leaves of the wall bellflower are fresh green and sharp-toothed. They are usually shed over the winter or are at most wintergreen, i.e. they adhere to the shoots until new shoots appear next year.
From about June to August, the funnel-shaped, broad-pointed flowers of the wall bellflower open in violet-blue – both in the wild species and in the various cultivars. They appear in great numbers and cover the entire plant. In autumn, a beautiful second bloom often appears.
In the wild species Campanula portenschlagiana, so-called poricidal capsules develop from the flowers. This is a rare form of capsule fruits, which is only formed by a few plant genera. The wall bellflower throws out its numerous seeds through holes in the capsule walls. However, some cultivars are sterile, so they do not produce seeds.
Wall bellflower – cultivation and care
Like most rock garden plants, the wall bellflower prefers a sunny or at least light to partially shady place.
A permeable, clayey, nutritious and rather fresh soil is ideal, but the wall bellflower is quite tolerant of the subsoil as long as it is not too wet. Too heavy soils are improved with sand before planting. Once grown, Campanula portenschlagiana can also withstand dry phases quite well.
Planting wall bellflower
Wall bellflowers can theoretically be planted from spring to autumn. However, avoid planting during dry periods. Place the perennials at 20 to 30 centimeters (8 to 12 in) apart and preferably in small groups of three to five.
Wall bellflowers are extremely easy-care plants that do not require special attention. If they grow beyond the edges of the bed, you can simply cut off the protruding shoots. In addition, you will of course need to pluck the weeds from the loose cushions from time to time.
In spring or autumn you can divide your wall bellflower. At the latest, when the plants become sparse or flower less abundantly, you can rejuvenate and revitalize the plants in this way. In addition, if the cushions have spread too much in one place, you can contain them.
The cushions of the wall bellflower can be easily propagated by dividing them. In spring or autumn, take the root ball out of the ground with a spade or digging fork and separate it into several pieces. You can then replant them. The wild species and some varieties (for example ‘Blue Magic’) can also be propagated by seed. The seeds can be sown at any time. The seed is covered with soil and kept evenly moist at about 20 °C / 68 °F. Bellflowers germinate quickly, then keep cooler.
Diseases and pests
Wall bellflowers are very healthy, robust and resistant plants.
Wall bellflower is hardy down to -32 °C / -25 °F.
Use in the garden
Wall bellflower can be used in a variety of ways in garden design: it looks good on the edges of perennial beds, as underplanting of high-stem or tree trunks or in rock gardens, as well as in wall cracks and ground joints. Wall bellflowers are also suitable for grave or slope planting. They also feel at home in the potted garden on the balcony and terrace. Other perennials such as lilacbush (Aubrieta), candytuft (Iberis), basket of gold (Alyssum saxatile) or mossphlox (Phlox subulata) are suitable planting partners. When they have faded, the wall bellflower takes over. Simultaneously with it, thyme species, creeping baby’s breath (Gypsophila repens), Balkan yarrow (Achillea ageratifolia) or woolly yarrow (Achillea tomentosa) show color.
The best known and most common variety ‘Birch’ or ‘Birch Hybrid’ is probably a hybrid of Campanula portenschlagiana and Campanula poscharskyana and therefore wintergreen. The flowers are violet-blue as in other cultivars, like ‘Catharina’ and ‘Nice to See’. The somewhat lower ‘Resholt’ is particularly dark, while ‘Lieselotte’ is somewhat lighter. The flowering time of all varieties is between June and August with partial afterblooming. Blue Magic’ even lasts until September.