Horticulture Magazine

Campanula ‘Bellflower’

light purple campanula flowers
By CHRIS LEE
Chris Lee, MA - Gardening Writer

Chris is a gardening writer and nature enthusiast. He graduated from Oxford Brookes University in 2022 with an MA in Psychology. Chris works with the Leeds Green Action Society, helping their food cooperative by growing various fruit and vegetables on their two allotments in Hyde Park, Leeds.

/ Updated May 2nd, 2023
Reviewed By COLIN SKELLY

Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.

/ Meets Our Editorial Guidelines

Campanula, Latin for ‘Little Bell’, is a plant that brings a cascade of colour to any garden.

It offers bold blues and purples, right the way through to proud pinks and whites.

You’ll also hear this plant called the ‘Bellflower’, alluding to the bell shape the flowers take before opening.

When they do eventually open, they reveal enticing star shapes, making Campanula a pleasure to look at throughout the year.

Overview

Botanical NameCampanula
Common Name(s)Bellflower
Plant TypePerennial Flower
Native AreaTemperate and subtropical northern hemisphere
Hardiness RatingMostly H5-H7
FoliageSome evergreen, some deciduous
FlowersBell-shaped flowers, often blue, purple, pink or white
Flowering MonthsJune, July, August
Sunlight

Preferred
Full Sun / Partial Shade

Exposure
Exposed or Sheltered

Size

Height
0.5 – 1M

Spread
0.1 – 0.5M

Bloom Time
June – August

Soil

Preferred
Most Soil Types

Moisture
Most prefer well drained

pH
Any except highly acidic

Technically speaking, the term ‘Campanula’ refers to plants from the family Campanulaceae that are known as bellflowers.1Introduction to the Campanulaceae. (n.d.). Bellflowers and Lobelias. Retrieved March 13, 2023, from https://ucmp.berkeley.edu/anthophyta/asterids/campanulaceae.html

Other plants from the family include lady bells, harebells, and hundreds more.

Campanula plants have a lot of versatility: some are deciduous, while others are evergreen; some are bushy, while others form clumps.

A carpet of Carpatica looking resplendent
C. carpatica

You can find annual, biennial, and perennial varieties, ranging in size from 5cm to over 2 meters.

None of the plants in this guide reaches quite that height, but more on that later.

How To Grow Campanula

Campanula is a relatively easy plant to introduce to a British garden.

Its growing conditions are not particularly fussy, so as long as you take a bit of time to understand the best time and place to plant it out, you should be good to go.

It’s very hardy, too – all varieties of Campanula sit between H5 and H7 on the RHS Hardiness scale – making them suitable for all but the harshest of climates in the British Isles.

Loddon Anna variety of campanula
C. ‘Loddon Anna’

For the vast majority of British gardeners, these plants can therefore be grown as perennials.

Propagation

You can propagate most varieties of Campanula by division in spring and autumn, or by basal cuttings in spring.

C. carpatica can be propagated by seed.

harebell Campanula rotundifolia growing wild

It’s good to divide your plants every three years or so to prevent overcrowding.

Soil Requirements

Chalky, loamy soil suits all varieties of bellflower.

Some types will take to soil with sand or chalk present, too.

All varieties can grow in alkaline or neutral soil, and a few can tolerate mild acidity.

In terms of drainage, this plant prefers moist but well-drained soil.

Particularly sensitive varieties will require well-drained soil, but these are in the minority.

Planting

When To Plant

The best time to plant bellflower is in spring – once the soil has started to warm after winter.

purple flowers of Campanula portenschlagiana in a garden bed

To give your plants a head start you can grow them in seed trays, beginning a few weeks before the last frost is expected.

Where To Plant

There is no hard-and-fast rule for where to plant a bellflower.

  • Some types – like ‘Stella’ – like exposure.
  • Others (‘Loddon Anna’, ‘Prichard’s Variety’) prefer shelter.
  • Others, still, can thrive in either condition.

Because of this, different varieties prefer different aspects – it is best to understand which variety you have chosen to grow and the conditions it prefers.

purple bellflower plant with many buds yet to flower in garden soil

There is one trait all bellflowers share, however: none will thrive in full shade.

Planting Out

If you’re planting seeds directly into the garden, use a dibber to create a hole a couple of centimetres deep.

Water thoroughly and stay attentive until seedlings start to appear.

Planting from a division is easy, too: just dig a hole large enough for the plant and its root system, place it in, and cover it over.

bushy wall bellflower plant with tiny purple flowers in a garden border alongside a brick path

Make sure it is planted at the same depth as it was previously, as planting too deep can cause damage.

Plant Care

Bellflower responds well to a bit of compost in spring, then again in mid-summer, so just make sure you water thoroughly after each dressing.

Mulching around the base of your plant will strengthen growth and maintain healthy soil conditions.

lilac flowers of Campanula persicifolia

Leave a couple of inches in diameter around the stems.

Pruning

Pruning requirements differ between bellflower varieties.

With some – like the C. carpatica – you don’t need to prune at all.

Others (‘Stella’) need to be cut back after flowering to maintain their optimal shape.

Pruning other varieties will prevent them self-seeding, and will encourage a second wave of flowers after the first wave begins to dwindle.

Common Problems

You can minimise the likelihood of your plant contracting most diseases by keeping it generally healthy. This means:

  • Keeping the soil well-watered, so the plant has moisture.
  • Keeping the soil well-drained, so the plant doesn’t have too much moisture.
  • Ensure enough access to sunlight.
  • Leave space between plants to reduce density and overcrowding.
  • Don’t use too much nitrogen in your fertiliser.
Slugs & Snails 

No one likes slugs or snails, but sadly they like pretty much every plant in your garden.

Both are active year-round and will munch unsightly holes in the leaves and stems of your bellflower plant.

Keeping them at bay is the goal of all gardeners, but their prevalence makes it an ongoing job.

You can use products like Nemaslug to target both, as Master Horticulturist Colin Skelly shares:

slug on the flower of a purple coloured campanula

“Nemalsug is a parasitic nematode in solution applied to the soil.

Rather than a chemical action, this method of control uses a specific parasite to target slugs and snails.

We are changing our thinking to regard slugs and snails as a part of the garden ecosystem instead of as pests, using targeted use of non-chemical controls or just accepting damage as the price of providing a food resource for other species.”

Other gardeners create barriers of crushed up eggshell or attempt to make beer traps that will lure in and drown slugs and snails before they damage your garden.

Aphids

Another ubiquitous garden pest, aphids suck sap from plants they inhabit.

They’re visible to the naked eye, so scanning your Campanula occasionally offers protection from unexpected infestation.

You may also see symptoms of their sap-sucking first: curled or distorted leaves, black sooty moulds, and generally poor health.

Other less pestilent bugs can keep aphids at bay, and at certain times of the year, this removes the need for any other intervention.

If it’s the wrong time of year or you don’t trust these other bugs to keep things in check, pesticides can be deployed.

Powdery Mildews 

If you find a coating of dusty white powder on the leaves of your Campanula, it may be a victim of powdery mildews.

This disease is caused by fungal infection, and although many plants are susceptible, it’s interesting to note that the fungus is different in each case.

powdery mildew on the leaf of a plant

The best way to prevent infection is to destroy infected leaves when they fall from the plant.

This will get rid of the spores that cause infection, as will pruning out shoots that are infected. Various pesticides are available, too.

Keeping the plant healthy will reduce the risk of powdery mildews.

Rust 

This is a very common garden disease which will reduce your plant’s vitality, then, if left unchecked, gradually kill it off.

It can affect leaves, stems, or flowers – so keep a careful eye on your whole Campanula plant.

Removing affected leaves can help keep early infection at bay, but if you remove too many you’ll damage your plant.

If things have progressed to this stage, fungicides can be used to prevent further spread.

Make sure not to compost any infected material, as the spores are durable and may infect other parts of your garden.

References

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