Bellflowers, known botanically as Campanulas, are a large group of cool climate perennials. Depending on the variety, they may be used in perennial borders, as a small scale groundcover, or naturalized in woodland settings. Bellflowers symbolize love and affection and were often given to someone to express gratitude. Whether you're interested in flower symbolism or not, if you're a fan of blue or purple flowers, this is definitely a plant to consider for your garden.
Bellflowers are very cold hardy and do best in areas where summers are not too sweltering. As the name would suggest, they typically have bell-shaped flowers, usually in bluish tones, and nondescript lance-shaped leaves, though there is a surprising diversity of form among the different varieties.
Most prefer to grow in full sun, although all appreciate light shade at the southern end of their range. Rich, moist soil is the key to growing bellflowers successfully. Early summer is the primary blooming period, but with a bit of deadheading, they often bloom sporadically throughout summer and into early fall.
Low, Spreading Bellflower Varieties
Groundcover forms of bellflower look great cascading over a low stone wall, spilling out of a hanging basket or used as edging in front of a bed of taller perennials.
- Dalmation bellflower (Campanula portenschlagiana) is one of the smallest species, growing only four to six inches tall and spreading widely. It is a blue or purple bellflower with upward-facing blossoms and fine, dark green foliage.
- Serbian bellflower (Campanula poscharskyana) is similar but grows as a groundcover up to one foot tall.
- Fairies' thimbles bellflower (Campanula cochleariifolia) has nodding white, blue or purple blossoms that rise on delicate stalks above a low mat of foliage.
- Creeping bellflower (Campanula rapunculoides) is a spreading purple bellflower. Like all bellflowers, it's attractive to pollinators. And it is definitely hardy... too hardy, in some areas. Some states list creeping bellflower as a noxious weed, so keep this in mind if you're considering it for your garden.
Upright Bellflower Varieties
Growing anywhere from two to five feet in height, these bellflowers grow as small clumps. They are taller than they are wide and are a good choice for mixing into a perennial border.
- Peachleaf bellflower (Campanula persicafolia) has one-inch bell-shaped blossoms that face straight out from 30-inch stalks rising above a low clump of foliage. Blue, pink, white and purple forms are available.
- Milky bellflower (Campanula lactiflora) grows up to five feet tall with bell-shaped, indigo-colored blossoms that stick straight up from the end of the stalks.
- Spotted bellflower (Campanula punctuata) is known for its larger blossoms, which nod downwards from the top of two-foot stalks. They come in pink, purple and blue forms.
Other Bellflower Varieties of Note
There are a few bellflowers that don't fit neatly into typical classifications. The three varieties below are some of the most heat tolerant bellflowers and do well in filtered shade.
- Korean bellflower (Campanula takesimana) grows as a tall groundcover, two to three feet in height with three to four-inch blossoms and heart-shaped leaves.
- Pink Octopus is an unusual cultivar with spidery pinkish-red flowers on 10-inch stalks. It spreads via underground runners and is useful for naturalizing in dry shade gardens.
- Clustered bellflower (Campanula glomerata) grows about two feet tall, bears the classic blue bellflowers on erect stalks and needs constant moisture to thrive.
Bellflowers are best planted in either early fall or spring. You can usually find them in local garden centers that are located in climates where bellflowers grow best. However, you will find your best selection through a seed catalog. They're fairly easy to start from seed, but can take up to 30 days to germinate.
Sow seed indoor in early spring and transplant when the seedlings are six to eight weeks old.
Maintenance and Potential Challenges
Besides removing the spent flower stalks to encourage repeat blooming, bellflowers are fairly low-maintenance plants. They need nutrient rich, evenly moist soil and full sun to partial shade.
Campanulas are prone to most of the typical garden pests, like slugs, mites and aphids, but not especially so. If these get out of control, garden centers are full of products to combat them - diatomaceous earth for slugs and insecticidal soaps for mites and aphids are two of the top non-toxic products available.
The most common problem gardeners experience with bellflowers is that they grow too well and take over areas where they are not wanted. Most will spread by seed, which is a desirable trait when they are planted in a naturalized environment, but it becomes a problem in small, highly managed flowerbeds. The groundcovers spread by underground rhizomes and can slowly colonize an area where growing conditions are ideal, Korean and creeping bellflower being most notorious for this trait.
The groundcovers can be difficult to remove where they are not wanted, but on the whole, bellflowers are not a plant that is considered highly invasive in the sense that they invade natural areas. If you do plant a more prolific variety, monitor it carefully to keep it from spreading too much.
- Remove spent flowers before they go to seed.
- Regularly check around the plant for any runners that sprout from the main plant. Dig these out.
- If growing Korean or creeping bellflowers, consider planting them in an area where they can't spread as easily, such as a trough or container. Other members of the campanula family aren't really an issue, so you won't need to worry as much about them spreading.
Dividing Bellflower Plants
Bellflower spreads over time, and to grow best, and to ensure that they don't take over the area in which they're planted, it's usually a good idea to divide them. The clumps can be divided every few years to keep them healthy. As a bonus, dividing will result in more bellflower plants for your garden.
Dividing bellflower plants is fairly straightforward.
- Dig around the outside of the clump of bellflowers, digging to at least seven inches deep to ensure you're getting most of the roots.
- Pull the plant out of the hole and use a garden knife or spade to divide the clump. Depending on how large the clump is, you can divide it into two pieces or more. Just make sure each clump has a section of the roots and rhizomes attached.
- Re-plant the original plant, as well as any divisions you made into their own holes. Plant them at the same depth they were originally growing.
- Water well.
Perfect Plant Companions for Bellflower
There are many plants that need the same conditions as campanula and look beautiful when planted together. Consider planting bellflower with Shasta daisies, lamb's ear, columbines, yarrow, lady's mantle, or garden phlox.
A Pleasing Palette
Bellflowers don't get as much attention as many other perennial species, but they have a lot to offer. With so many forms and colors to choose from, they fill a garden designer's palette with a rich array of options.