Creeping bellflower (Campanula rapunculoides) is a perennial that reproduces both by seed and creeping roots. It may be confused with native harebells, but this weed bears its flowers in a long, showy spike, while harebells are borne singularly or in a loose spike.
Stems are erect, purplish in colour and grow to 1m or more tall.
Leaves are borne alternately and visually differ based on location on the plant. Lower leaves are stalked, heart-shaped and have coarsely-toothed margins. Upper leaves have no stalks and are lance-shaped with hairs on the lower surface.
Flowers and Fruit
Creeping bellflower has attractive, nodding, purple bluebell-type flowers borne in long spikes. Flowers are composed of five united petals. Its fruit is a round capsule containing many light brown, winged seeds that spread easily by wind.
Creeping bellflower is adapted to grow almost anywhere. It can push its creeping roots under fences, through lawns and even underneath concrete and sidewalks. It can grow in both full sun and full shade.
Once established, creeping bellflower is almost impossible to eradicate due to its extensive root system and resistance to 2,4-D.
Watch for creeping bellflower in wildflower mixes. Never purchase wildflower mixtures that don't list all species on the label. This invasive plant may also be sold at nurseries, or may hitch a ride along with other perennials. Never use this plant as an ornamental in your yard; there are many other blue flowers that are non-invasive, such as Smooth Blue Penstemon or Blue Mirror Delphinium.
Hand-pull and bag the flower spikes before they bloom to prevent seed production. Dig out as much of the roots as possible and keep pulling the stems as they re-sprout; the plant will eventually starve and die.
Creeping bellflower is resistant to 2,4-D, which is a common component of garden centre weed killers. Glyphosate may be used for spot applications but it will kill all competing vegetation as well.