Dalmation bellflowers (Campanula portenschlagiana) are low-growing herbaceous perennial flowers that are often used as edging plants in perennial borders, to spill over stone retaining walls, or to fill in gaps between stepping stones. Like other members of the very large Campanula genus, Dalmation bellflowers have dark green leaves and purple or blue cup- or bell-shaped flowers. This plant often blooms from late spring nearly into fall. In many climates, they are virtually evergreen, since new leaves are constantly replacing old leaves as they fade and turn brown.
- Botanical Name: Campanula portenschlagiana (formerly known as C. muralis)
- Common Names: Dalmation bellflower, Adria bellflower, wall bellflower,
- Plant Type: Herbaceous perennial flower
- Mature Size: 3 to 6 inches tall, with a width of 6 to 12 inches
- Sun Exposure: Full sun to part shade
- Soil Type: Medium moisture, well-drained soil
- Soil pH: 6.6 to 8.5; neutral to alkaline
- Bloom Time: May through June
- Flower Color: Violet and blue
- Hardiness Zones: 4 to 8 (USDA)
- Native Area: Dalmation mountains of Croatia and Herzegovina·
Because it has weak stems and an ability to spread via rhizomes, the most natural use of this perennial is as a ground cover, where it can be used in rock gardens, as an edging plant, or atop stone walls. Or, install the plants along the rim of a container garden and let them cascade down over the sides. Alternatively, if you do not wish to treat them as a ground cover and want them to attain greater height, you will have to provide support (a peony ring would work well here).
Dalmation bellflower should be planted in average well-drained soil that remains consistently damp but not soggy. They generally like full sun, but in warmer climates, they will perform better if given some shade.
In ideal conditions, this plant will spread fairly quickly, both by extending its rhizomatous roots and by self-seeding. If blooming tapers off as the summer progresses, sheer the plants to induce additional flowering. Regular deadheading of spent flowers will also help prolong the bloom period.
This plant thrives in full sun to part shade; the hotter the climate, the more it will appreciate some shade. This Campanula species tolerates more shade than most others.
This plant prefers moist but well-drained soil, but does fairly well in average soil types without much organic material.
Dalmation bellflowers have typical needs for water. About 1 inch of water per week, in the form of rainfall or irrigation, will keep them blooming. Once well established, dalmation bellflowers can tolerate short periods of drought.
These plants perform badly in climates with hot humid conditions where night temperatures may remain above 70 degrees Fahrenheit.
A spring application of organic fertilizer or a layer of compost will provide all nutrients necessary. This is a hardy plant that doesn't require much feeding.
Dalmation bellfowers will readily self-seed, and the offspring plants can be carefully dug up and transplanted to other locations.
It is also quite easy to propagate bellfowers by dividing them. Simply cut way a portion of the plant clump at the perimeter, making sure to get both foliage and a section of roots, then transplant the section immediately to a new location. Make sure the roots are fully buried.
- Campanula portenschlagiana 'Aurea' is one of the most popular cultivars. Commonly called golden Dalmatian bellflower, it has attractive golden spring foliage that gradually acquires green tones as the growing season progresses.
- C. portenschlagiana ‘Birch’s Hybrid’ is a more upright plant with true blue flowers, with tinges of purple at the margins.
- C. portenschlagiana ‘Resholdt's Variety’ is a slightly larger plant, growing to 12 inches high, with lilac blooms.
A number of other species of Campanula can also make good ground cover plants:
- Campanula poscharskyana is quite similar to C. portenschlagiana, but it a taller plant, at 12 inches in height. This plant goes by the common name Serbian bellflower.
- C. carpatica is a mound-forming bellflower that grows to a height of about 12 inches, and is available in white cultivars. Although not creeping spreader, its clumps can be frequently divided and replanted to cover larger areas of ground. This species is commonly known as Carpathian bellflower or tussock bellflower.
Common Pests and Diseases
Dalmation bellflowers are sturdy plants that have few serious insect pests or diseases, but slugs and snails often enjoy feasting on the leaves.