Blue flowers can be hard to find, and easy-to-grow blue flowers even more so. If bell-shaped blooms, pollinators, and blue hues are your thing, discover bellflowers (Campanula). Learn how to plant, grow, and care for this bell of the garden.
About Bellflowers
Bellflowers are members of the genus Campanula, which comes from the Latin “little bell.” The bells vary from open saucer to pixie cap to tubular. They’re loved by bees, butterflies, and hummingbirds and function as excellent pollinator attractors when planted en masse.
Bellflower blooms are five petals fused at the base and can be on tall spikes or arrayed individually on the plant, depending on the species. Most flower from midsummer to autumn. They are cold-hardy and can survive in USDA zones 3 to 8.
The genus has hundreds of species! They can be perennials, biennials, or annuals! Whether short groundcovers or tall prairie plants, most are covered in light blue, lavender, or purple bell-shaped flowers, although white varieties are also available.
Due to their wide range of variety, they are versatile, adding fairy-like beauty to woodland edges, paths, bed borders, fencing (taller varieties), rock gardens, and as the spiller in hanging baskets.
Bellflowers can be planted outdoors once the spring frosts have passed, and perennial varieties can also be planted 4-6 weeks before the frosts in fall to allow time for new roots to establish before the plant goes dormant. Harden off potted plants for a week prior to transplanting.
Where to Plant Bellflowers
Bellflowers enjoy full to partial sunlight and will thrive in the dappled light at the edge of the woods. In the warmer areas of their range, plant them in locations with afternoon shade to give them a break at the hottest time of the day. They aren’t picky about soil conditions, except that they need well-drained soil. Be careful not to plant in water-logged areas. A neutral pH range is fine.
Use bellflowers to provide the garden with those hard-to-find blue hues, setting off the more common yellows and oranges.
How to Plant Bellflowers
Bellflowers are easy to find at nurseries and garden centers in spring and can be ordered in small pots online. Plant potted bellflowers just as you would other small annuals or perennials, taking care to choose the appropriate location. Spacing will vary depending on the mature size of the cultivar you selected.
For established plants:
Prepare the area by removing roots, rocks, and weeds. Loosen the soil and work in a few handfuls of compost.
Dig a hole as deep as the root ball and twice as wide.
Remove the bellflower from its container and prune any circling or girdling roots.
Place the bellflower in the hole to check the depth–it should rest even with the top of the ground.
Backfill the hole, ensuring no air pockets form around the roots.
Water thoroughly, then apply mulch around the plant to hold soil moisture and keep weeds down.
To start Bellflowers from seed indoors:
Begin 6 to 8 weeks before your last frost in spring.
Sow bellflower seeds in trays or cell packs in a standard seed starting mix.
Lightly cover seeds with a dusting of vermiculite, but don’t bury them–they need light to germinate.
Cover the tray with a humidity dome or plastic wrap to preserve moisture until germination, then remove the cover.
Harden off seedlings prior to transplanting outdoors.
Growing
New bellflowers will need weekly watering in spring and early summer until they are established. They prefer evenly moist but not soggy soil. With proper mulching, they should be fine receiving the same watering as the rest of the garden, whether that’s rain or from your irrigation.
Some types of campanulas need support. If so, stake when growth is two-thirds complete.
Trim off dead stems and vegetation in early spring before the plants break dormancy.
As blossoms fade, deadhead the more visible tall varieties or container plantings; this will promote more flowers and prevent self-seeding. Most varieties can be cut back to the base. With Campanula lactiflora, just pinch off the top blossoms for more blooms. If you give them the “Chelsea chop” in late spring (cutting down by one-third), they will flower again.
Bellflowers do need some TLC. If left untended, they will fade away. To avoid this, take cuttings every three years (in springtime) and propagate if you wish.
Types
Tall bellflower (C. Americana) is a prairie native biennial. It grows well in partial shade and reaches 3-5 feet tall in the second year. Although a biennial, it often self-seeds, maintaining a presence in the garden or meadow.
‘Takion Blue’ (C. persicifolia) is a peach-leaved bellflower that forms a mounded shape about 12-16 inches tall and wide. It’s hardy in zones 4-8 and covered in upright lavender-blue flowers. It’s often called Fairy Bellflower or Fairy Bells. Can you see w
Dalmatian bellflower (C. portenschlagiana) is a fantastic trailing species. It is semi-evergreen, hardy in USDA zones 3-8, and perfect for trailing over the edge of hanging baskets or rock walls.
‘Rapido Blue’ (C. carpatica) is a groundcover type of bellflower best planted in groups. It stays only 5-8 inches tall and not much wider and is super cold-hardy.
The best border bellflowers are named forms of Campanula lactiflora.
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Wit and Wisdom
Bellflowers vary widely in mature size–double-check the tag to make sure you’re getting the right one for the spot you’re considering.
Trailing bellflowers make an excellent alternative to petunias for a hanging basket in a partially shady location.
Avoid the non-native Campanula rapunculoides, also known as creeping bellflower. In many areas of the US, it is an aggressive invasive species that can be quite problematic.
Andy Wilcox is a flower farmer and master gardener with a passion for soil health, small producers, forestry, and horticulture. Read More from Andy Wilcox