The genius campanula commonly known as bellflower encompasses a large selection of perennials, biennials and annuals. Some varieties are garden friendly, others need controlled and then there are the ones that should only be used in places where nothing else grows such as dry slopes or deep shade. Of the last group, campanula rapunculoides, commonly known as creeping bellflower or Rocky Mountain bluebell is on the Alberta’s noxious weed list. This hardy plant has escaped from homesteads throughout Alberta and is making its way into pastures and fields. The plant is also commonly found in older yards. It spreads by rhizomes and withstands drought conditions.
Bellflowers are easily identified by the shape of their flower tubular, bell or star shaped. The most common flower color is blue but dependent on the variety campanulas are available in white pink, and different shades of purple.
Growth habits are, upright, hanging or clumps. It depends on the variety or sometimes even the cultivar if the roots spread quickly by rhizomes or stay in a localized area.
Clips, blue or white, campanula carpatica, is a popular variety that is hardy to Central Alberta. The plant grows in clumps that need to be split every three of five years depending on the soil conditions and the amount of sunlight it receives. If the clump is allowed to grow too large the flowers slump to the edges leaving a bare spot in the middle. Clips will thrive in full sun to partial shade. Place the plant near the front of the border as it is relatively short. In wet years, slugs can be a problem.
Older varieties of clustered bellflower campanula glomerate is commonly found in older neighbourhoods where it has been given or creeped between yards.
The plant is great to fill in large areas or places with poor soil but only named varieties that are purchased from a reputable seller should be used in a flowerbed.
Named varieties have been chosen as they do not have aggressive roots and will stay in small clumps. The plants are available in white or purple and reach a height of 12 -14 inches (30 – 35 cm).
Peach-leafed bellflower campanula persicifolia spreads through shallow roots that spread outward making a larger clump but can be easily controlled.
Take time to deadhead as seeds are viable and can lead to a large number of plants.
The plant itself consists of low growing leaves coming from a central point.
Strands of flowers start appearing in early July and continue can continue into August depending on the weather and plant location. Look for this plant in blue, white and with single or double flowers.
Harebells, campanula rotundifolia, are native to Alberta. Do not dig these in the wild to move into a flowerbed as the plants do not adapt to the richer garden soil and less plant competition. Purchase varieties on the market that have been selected for domestic use. Harebells have very slender stems that hold one or two bells aloft. Their roots will spread outwards but they will grow well in clumps adding a blue clump to the garden for a couple of weeks. Deadheading is necessary as the plants come easily from seed.
Canterbury bells are a biannual which means that it becomes established the first year and blooms the second. Expect the flowers, white, pink or blue to start blooming in the spring and continue into the summer. The height of plant depends on the variety but it will range between 24 to 36 inches (60-90 cm). The large flowers and stunning display make waiting a year worthwhile. Place the plants in a location where they will be covered with snow during the coldest months. Exposed plants are prone to winterkill.
There are a few varieties of campanula that can be a problem but for the most part, the add color and shape to the garden. Know the plant before adding it to the garden.
Linda Tomlinson is a horticulturalist that lives near Rocky Mountain House. She can be reached at your_garden@hotmail.com