Campanula (typically called "clustered bellflower") is a showy garden flower with abundant bell-shaped blooms. Once you get them established in the correct spot, this flower is a low-maintenance favorite that will come back year after year. Read on to learn all you need to know to grow and care for campanula in your garden.
What Is Campanula?
A genus campanula is a group of flowers that includes over 300 varieties! Some are annuals, and some are perennials. Some stretch upwards while others make a spreading ground cover. However, all of them have lovely, bell-shaped flowers that grow abundantly on each plant. They are typically lavender flowers shade or blue but can also come in shades of pink and white.
Most species of campanula will bloom from late spring to early fall. If you stay on top of deadheading them, you'll promote a thicker cover of blooms. Some species are aggressive seeders, and you should be sure to remove their seed heads before you find yourself with more of these blue flowers than you intended!
Campanula Care Requirements
To get the thick mass of blue flowers that campanula are known for, plant the tiny seeds in a bed that will receive full sun. They tolerate partial shade well, though, and will still add beautiful color to partly shaded borders in cottage gardens. Because they are heat sensitive, it's best to plant them so that they receive full sun in Northern zones but partial shade in Southern zones, and this will keep them from getting scorched from noonday heat in the hotter areas.
You will likely not need to supplement your regular rainfall in the spring and fall. Campanulas can tolerate short periods of drought, but if your summer is particularly hot and dry, expect to water them once a week.
These cool-loving plants don't do well with heat, and some varieties are more heat-tolerant than others. In general, they do best in USDA zones four and up.
Campanulas prefer well-drained soil with moderate moisture, and any pH range is fine, even highly acidic soil. Because these plants are so tolerant of soil types, they are often planted in rock gardens, where soil quality might be lacking.
You can grow campanula through seeds or rhizomes. The seeds can be planted shallowly in a prepared garden bed after the last frost date. Keep the soil moist until the seedlings have gotten established. If planting with rhizomes, merely cut them from the original plant at a root note, and rebury the roots in their new location.
Campanula is susceptible to a few of the basic garden pests and diseases. Here are a few to keep an eye out for.
Powdery Mildew and Botrytis
These fungal diseases, like most others, are caused by an excess of moisture and lack of air circulation. Botrytis, in particular, is unique in that it requires cool moisture. To treat, thin out the area of your campanula if it's gotten overgrown. Remove any affected leaves, and consider applying a fungicide.
Campanula is particularly prone to slugs. You'll be able to find them at night, to handpick them from the plants. To trap them, dig a hole in the ground and place a bowl with steep sides in it. Fill it partially with beer, and let it sit overnight. Slugs will be attracted to it but will not be able to get back up the steep sides of the dish and will drown.
Is Campanula Pet Friendly?
Yes! No part of the Campanula plant is toxic to either wildlife, pets, or people.
Campanula Iatifolia (Wide-Leaved Bellflower)
This tall campanula variety reaches a height of 4 feet and is excellent in the back of flower beds. It has some of the deepest purple-blue flower hues and reseeds readily. So readily, in fact, that some zones consider it invasive!
Campanula punctata (Spotted Bellflower)
This bellflower has one of the most pronounced bell shapes, hanging downwards in narrow cones. The flowers are usually pink, with purple spots inside. The Spotted Bellflower is more sensitive to heat than other varieties and will self-seed and spread vigorously.
Campanula Poscharskyana (Serbian Bellflower)
The Serbian bellflower is a great choice for ground cover. It spreads by runners and only reaches 6 to 12 inches in height. The lilac-blue blooms open up to become star-shaped flowers.
Campanula lactiflora (Milky Bellflower)
The Milky Bellflower comes in shades of blue and violet, but also white - hence the name. It's not tolerant of hot weather. This is one of the taller varieties, reaching up to 5 feet in height, and it will likely need staking.
Campanula Carpatica (Carpathian Bellflower)
Named for the Carpathian mountains, the deep blue, cup-shaped flowers on this campanula open widely. It prefers cool temperatures and will require mulch to protect its roots during the summer. It has a lower profile than other varieties, topping out at 1 foot tall.
Campanula Persicifolia (Pink Octopus)
Looking for a pink bellflower? The Peach Leaved Bellflower, also known as "Pink Octopus", is a good choice. The blooms are a soft pink, almost white. It's a great choice for flower beds beneath trees, as it handles shade well. It grows fast but can get a bit leggy.
Campanula Portenschlagiana (Dalmatian Bellflower)
This is the shortest species of campanula on this list, topping out at 6 inches, and its height makes it great for edging gardens and sidewalks. It's a spreading bellflower, propagating primarily through rhizomes. The deep lavender-blue flowers open into a star shape.
Campanula Pyramidalis (Chimney Bellflower)
This is one of the tallest perennial campanulas, and it can easily reach five to six feet tall that offers pale blue bell-shaped flowers. It is also a short-lived perennial and best treated as a biennial.
Campanula Takesimana (Korean bellflower)
Takesimana is a less invasive alternative to Campanula punctata with a similar appearance. Both range in color from white to pink to maroon with bell-shaped flowers. This variety offers medium height and is inclined to spread vigorously, so plan accordingly.
Campanula Garganica (Adriatic bellflower)
This species of campanula creates a sea of starry blooms all summer, making this plant a great option as a soft backdrop for taller and bolder plants. It offers beautiful blue and purple flowers, and this plant can grow up to 3-5 feet tall.
Campanula divaricata (Appalachian bellflower)
The Appalachian bellflower is a perennial wildflower native to the eastern United States that produces small blue flowers in late summer. Once it is established, it can tolerate dry and even drought conditions.
Campanula Primulifolia (Spanish Bellflower)
This is one of the few species that will thrive and prosper in hot and dry conditions. It is an easy and low-growing campanula with pretty purple star-shaped flowers. This vigorous plant can form a dense, vertical shrub reaching three feet or more.