Creeping Bellflower chokes out other plants

Lauren Bethke

Creeping bellflower, or Campanula rapunculoides, is a deceptively charming perennial that has become notorious in south Minneapolis. With its bell-shaped, bluish-purple flowers and tall, leafy stems, it can be quite pretty, but unfortunately it is non-native, fast-spreading, and difficult to control – and it can choke out native plants. Late summer is a great time to work on removing creeping bellflower from your yard, boulevard, alley, and public spaces!
What does creeping bellflower look like? The plant is native to parts of Europe and Asia, and was originally introduced to North America as an ornamental garden plant. It has tall spikes of purple flowers and heart-shaped, toothed leaves that alternate along the stem. It blooms from late spring to early fall.
Creeping bellflower also has a deep, extensive root system. The root system is composed of rhizomes and thick, tuber-like roots that can be up to two feet deep in the soil. The roots store energy, allowing them to re-grow new plants. This makes the plant extremely difficult to remove once it has become established.
Creeping bellflower is a big problem in south Minneapolis because of its aggressive growth habits. It can outcompete native plants and other desirable species, and its roots can choke out other plants. On top of this, its ability to reproduce by both seed and root fragments means it spreads rapidly. Even a few plants can turn into a widespread problem within just a season or two.
Creeping bellflower can be controlled or even eradicated, but it requires a multi-pronged approach. There is no single “magic bullet,” but with sustained effort, you can significantly reduce the amount of creeping bellflower in your yard.
The first method is manual removal - in other words, digging it up. Digging up creeping bellflower is very labor-intensive, but can be effective if done thoroughly. The key is to remove as much of the root system as possible. When removing by hand, use a garden fork or shovel to dig at least 12 inches deep. I find that using a sturdy fork when the soil is moist gives the best results! Sift through the soil carefully to remove all visible root pieces. Both the large rhizomes and small white root fragments can re-grow new plants, so be as thorough as possible.
Systemic herbicides containing glyphosate or triclopyr can be used to kill creeping bellflower, especially for large or dense infestations. These chemicals work by being absorbed into the plant and transported to the roots, killing the entire system. Personally, I try to avoid using chemicals in the garden as much as possible, but I do use a small amount of glyphosate (very carefully) on larger patches of creeping bellflower in my yard.
To use herbicides effectively, apply during the active growing season when the plant is flowering. Late summer to early fall is a good time to apply, since the plant is winding down and directing a lot of energy to the roots. Applying herbicide at this time can help draw the chemical into the roots as well, making it more effective. Follow all instructions on the herbicide label, and avoid spraying on windy days to prevent drift. You will likely need to apply an herbicide several times over a couple of growing seasons to get a creeping bellflower infestation under control.
You could also try smothering a patch of creeping bellflower by covering it with a thick layer of cardboard or newspaper. This can weaken the plant by depriving it of the sunlight it needs to survive. If you want to try this method, leave the cardboard or newspaper in place for at least a full growing season, or ideally longer. Although this can help slow the plant down, I know of people who have kept a patch of creeping bellflower covered for a year or more and still found it surviving underneath, so it’s probably not a full solution on its own.
No matter which method you choose, follow-up is essential. Regularly inspect the area for new growth and pull up any small new shoots as soon as they appear.
Even if you can’t eradicate creeping bellflower from the roots, just pulling the flower stalks is helpful to avoid seeds spreading and creating even more plants. Each plant can produce up to 15,000 tiny seeds if it is not pulled out in time. As I’ve been walking along East River Parkway the past few weeks, I’ve noticed that people have been pulling creeping bellflower from along the running path, which is a helpful step!
Additionally, check out the Facebook group “Creeping Bellflower Battles.” It’s a good resource that has a lot of south Minneapolis members sharing information and commiserating over this difficult species.
Creeping bellflower may be pretty, but it’s a big problem for our local landscapes. If each of us does our part, we can help eliminate this aggressive plant from our community’s natural spaces!
For more information, check out the University of Minnesota Extension Yard and Garden website. Extension resources are written by experts and contain the latest and most reliable research-based information. Happy gardening!