Bellflower (Campanula) – The Complete Guide

A prime example of flower-rich habitats, the bellflower does not let its gardener down.

The cosmopolitan among the perennials adorn the bed, the rock garden, the balcony, and the windowsill throughout the summer.

Care Tips

In order to enjoy the filigree flower carpet throughout the summer, bellflowers do not require extensive care.

If you pay attention to the following measures, Campanula will bloom in beds and pots for what feels like an eternity:

  • Keep the bellflower constantly moist without causing waterlogging.
  • During the flowering period, fertilize organically every 2-3 weeks with compost, horn shavings, or nettle broth.
  • Clean out withered flowers to attract a pretty repeat bloom.
  • Prune close to the ground in the fall or, better, in the spring before fresh shoots appear.

In exposed locations, the perennial should receive protection in the form of foliage, straw, or coniferous branches, despite its winter hardiness.

A bellflower in a pot or a window box should move to frost-free, cool, low-light winter quarters before the first frost.

During dormancy, water the bellflower only enough to prevent the root ball from drying out. Do not give any fertilizer during this phase.

Which Location is Suitable for the Bellflower?

The bellflower thrives best in a semi-shaded location, preferably protected from the full midday sun. This premise applies universally to the wide family of bellflowers.

If you adjust the location down to the last detail to the favored species and variety, the flower will reach its optimum.

For example, the clustered bellflower (Campanula glomerata), suitable for the rock garden, does its best in full sun or at least a sunny spot, while the wide-leaved bellflower (Campanula latifolia) prefers to linger in a cool, shady spot.

The Right Planting Distance for Bellflowers

The perfect planting distance should conform to the chosen bellflower species.

The following overview shows recommended distances in the bed for some of the most popular Campanula. If you plant the perennial in a balcony box, reduce the specified values by about 2 inches (5 cm).

  • Wall bellflower (Campanula portenschlagiana): Planting distance 8 inches (20 cm); 16 to18 pieces per 10 sqft.
  • Carpathian bellflower (Campanula carpatica): Planting distance 10 inches (25 cm); 16 pieces per 10 sqft.
  • Clustered bellflower (Campanula glomerata): Planting distance 14 inches (35 cm); 8 pieces per 10 sqft.
  • Spotted bellflower (Campanula punctata): Planting distance 16 inches (40 cm); 6-8 pieces per 10 sqft.
  • Milky bellflower (Campanula lactiflora): Planting distance 28-26 inches (70-90 cm); 3-6 pieces per 10 sqft.

What Kind of Soil Does the Bellflower Need?

Even though the requirements for light and temperature conditions may differ, in terms of soil all Campanula varieties largely agree. Thus, the ideal soil should be structured:

  • Deeply loose and humusy
  • Nutrient-rich and fresh-moist to moderately dry
  • Neutral to calcareous

Cultivated in a balcony box, hanging basket, or pot, the bellflower likes to spread its roots in loose compost-based potting soil, enriched with a little sand, expanded clay, or lava granules.

What is the Best Time for Planting Bellflowers?

The merry month of May is the best time to plant a bellflower in a perennial bed, rock garden, or along the edge of a grove.

From the middle of the month, the danger of late frosts in the soil is over, so that the young plants that you have grown yourself or bought ready can grow unhindered.

When is Flowering Time for the Bellflower?

The main flowering period of bellflowers extends from June to August.

With a little horticultural attention, you can extend the flowering period by several weeks into the fall.

You can achieve this feat by regularly cleaning out wilted flowers or cutting the perennial in half after the first flowering phase.

Pruning the Bellflower Properly

If you cut off wilted flowers regularly, the bellflower will respond with a vigorous rebloom.

Cut off the withered foliage either in the fall or in early spring to just above the ground. If the bellflower functions as a ground cover, prune in early spring using a lawnmower set to the maximum cutting height.

Attractive Campanula varieties, such as the Canterbury bells (Campanula medium), are also suitable as long-lasting cut flowers. Ideally, cut the stems in the early morning hours after the perennial has been watered.

Watering the Bellflower

The bellflower prefers a balanced water supply. Do not allow the root ball to dry out or drown in waterlogging.

To avoid damaging the fragile flowers’ beauty, avoid overhead watering. The bellflower readily accepts the irrigation water when you water directly to the ground with the spout of the watering can.

Fertilizing the Bellflower Properly

Since bellflowers are among the weakly consuming perennials, fertilization is of secondary importance for proper care.

If you administer a portion of compost or horn shavings in the bed every 2-3 weeks during the flowering period, the requirements are perfectly met.

In the balcony box or pot, an organic liquid fertilizer every 14 days completely covers the requirements.

Please note that you should not give any fertilizer from August onwards so that the bellflower can prepare for the winter.

Wintering the Bellflower

The multifaceted Campanula genus has a number of hardy species for the perennial bed that are completely winter-hardy. However, not all Campanulas have this attribute.

To be on the safe side in case of doubt, the following precautions for a safe wintering are recommended:

  • Leave the retracted foliage in place until spring as natural winter protection.
  • Pile Campanula with leaves, brushwood, or straw before the first frost.
  • In case of bare frost, water the plant on mild winter days.

In a balcony box or pot, there is always a risk of the root ball freezing behind the thin wall of the container.

Therefore, carry bellflowers in the container to frost-free, dark winter quarters. In this case, the withered foliage must give way, as it increases susceptibility to disease.

Propagating the Bellflower

Very few Campanula are suitable for classical propagation methods, such as division or cuttings. In contrast, sowing seeds is gratifyingly uncomplicated.

Starting in late February, follow these steps:

  • Fill a seed tray or small pots with peat sand, coconut fiber or seed soil.
  • Mix the very fine seeds with some bird sand and sow them.
  • As light germinators, just press the seeds or sift a maximum of 5 mm with sand or vermiculite.
  • Moisten them with a fine spray and place them in a half-shaded location in a greenhouse.

At a temperature of 68 to 77 °F (20 to 25 °C), the germination period takes 7 to 21 days. Keep the seeds permanently slightly moist and ventilate the mini-greenhouse daily.

From a growth height of 1-2 inches (3-5 cm), prick the seedlings out into individual pots.

The Bellflower in a Pot

In a pot, the bellflower sets the scene with floral splendor on a sunny or semi-shaded balcony. Plant bellflowers in loose potting soil, with drainage of clay shards over the water drainage in the bottom of the pot.

Here’s how to properly care for this pretty perennial:

  • If the top inch (2-3 cm) of the substrate dries out, water the plant.
  • From May to July, fertilize every 2 weeks with liquid fertilizer.
  • Clean out withered flowers for a repeat bloom.

Although many Campanula species are hardy, they will not survive the cold season outdoors in pots.

To prevent the root ball from freezing, move the bellflower into frost-free, dark winter quarters in the fall. Cut off all plant parts close to the ground beforehand to take the wind out of the sails of diseases and pests.

Is the Bellflower Poisonous?

The degree of Campanula‘s toxicity is still a matter of controversy. Until definitive findings are available on toxicity, we recommend vigilant handling of campanula.

Keep children and pets away from the flowers. All planting and maintenance should be done with gloves. Dispose of cuttings in the compost pile only if neither grazing animals nor horses can get to them.

Are Bellflowers Suitable As Houseplants?

The evergreen Italian bellflower (Campanula isophylla) is wonderfully suitable as a houseplant for hanging baskets thanks to its creeping growth with lush tendrils up to 8 inches (20 cm) long.

Also popular for indoor cultivation is the wall bellflower (Campanula portenschlagiana) with blue or white star-shaped flowers.

Other cultivars, however, are not always suitable for the home windowsill. Therefore, when buying, ask specifically whether the favored bellflower does not immediately flop at cozy warm room temperatures.

Is Every Bellflower Hardy?

The multifaceted Campanula genus has species and varieties that thrive in almost all places on earth.

Thus, you should not expect frost hardiness from Mediterranean bellflowers, while other specimens defy even bone-chilling frost.

Popular species with harmless winter hardiness are:

  • Carpathian bellflower (Campanula carpatica): Hardy to -40 °F (-40 °C).
  • Clustered bellflower (Campanula glomerata): Hardy to -49 °F (-45 °C).
  • Peach-leaved bellflower (Campanula persicifolia): Hardy to -31 °F (-35 °C).

Which Bellflowers Are Suitable As Ground Covers?

If you are on the lookout for bellflowers, which cover the ground with a flowering carpet with creeping growth, there is a multi-faceted selection of species and varieties to choose from.

Here is a selection of the most beautiful groundcovers at a glance.

Wall Bellflower (Campanula portenschlagiana).

Within a short time, this magnificent plant covers the sunny rock garden and the lean dry stone wall with a lush floral.

The up to 28 inches (70 cm) long tendrils are covered with violet-blue, large bell flowers from June to August and an after-bloom in September.

Milky Bellflower (Campanula lactiflora)

Wherever a flowery cushion planting is desired in sunny to partial shade, this handsome groundcover is at hand.

With white or blue star-shaped flowers, this runner-forming Campanula species is recommended as a contrasting underplanting to majestic roses or will wreathe your prettiest perennial bed as a striking border planting.

Beautiful Varieties

  • Blue Clips: Sky-blue Carpathian bellflower (Campanula carpatica) for the rock garden, hardy and robust; height of growth 8-10 inches (20-25 cm).
  • Sarastro: Dark purple flowering spotted bellflower (Campanula punctata) with flowers up to 4 inches (10 cm); growth height 28-40 inches (70-100 cm).
  • Alba: Clustered bellflower (Campanula glomerata) with pure white flowers in dense panicles on strong stems; height of growth 16-20 inches (40-50 cm).
  • Blue Bloomers: Semi-double flowers in bright violet-blue from June to August; height of growth 36-40 inches (90-100 cm).
  • Birch Hybrid: Magnificent wall bellflower (Campanula portenschlagiana), the ideal ground cover with a long flowering period; growth height 4-6 inches (10-15 cm).