Creeping bellflower (Campanula rapunculoides) is a pretty, hardy, disease-resistant perennial that grows readily in a variety of conditions. What's not to love about that, right?
Well, if you introduce this aggressive species to your garden, it won't be long before it chokes out your other flowers and proves almost impossible to eradicate. It has a fast-spreading and deep root system that becomes many gardeners' nemesis.
Brought over to North America from its native Siberia and Europe, it was initially a popular plant. Now that the extent of its aggressive nature has been discovered, it's classed as an invasive species across most of the country.
Some gardeners are drawn to the creeping bellflower as it's attractive to pollinators like bees and butterflies. These plants produce an abundance of seeds in the summer and they're easily distributed by these insects and even through gentle breezes.
However, it's the root system that makes it such a challenge to rid a garden of this species. Creeping bellflower has long tubers that grow deep into the soil. It also produces thin rhizomes that reach out into the surrounding ground alarmingly quickly.
Their rooting system can remain dormant for prolonged periods, lulling gardeners into a false sense of security. You may think you have gotten rid of the plants and then they suddenly spring up again the following year.
Before you know it they'll take over entire gardens, and infiltrate neighboring lawns, alleys, and sidewalks. The roots are capable of traveling over and around rocks, under fences, and in between pavers. Other plants struggle to compete when this species takes hold.
|Botanical Name||Campanula rapunculoides|
|Common Name||Creeping Bellflower, Rampion or Rover Bellflower|
|Plant Type||Perennial herbaceous species|
|Mature Size||Up to 3 feet|
|Bloom Time||July to September|
|Flower Color||Lavender or purple-blue|
Identification of Creeping Bellflower
Even though there are numerous bellflower species, the creeping variety is relatively easy to identify. The leaves found at the base of the plant are heart-shaped and become narrower and lance-like as they move upwards. They're also serrated, sometimes being described as 'toothed.'
The plants can reach up to three feet in height. The drooping bell-shaped flowers appear during the summer, growing up one side of the stem, and are usually found in shades of lavender-blue.
Where It's Found
Creeping bellflower grows pretty much anywhere. It can thrive in sun or shade and handles a variety of different soil types—even those that have poor drainage or are infertile. It's found in most parts of North America, other than the hottest southeastern states. Moist and shady locations are where the plant tends to be at its most invasive, though.
How to Remove Creeping Bellflower
Be prepared for a long haul when attempting to eradicate tenacious creeping bellflower. It can take several years of hard effort to eliminate this species, and some horticulturists choose to focus on managing it instead.
Removing The Roots
It's white, fleshy, insidious underground rhizomes and deep taproots can't simply be pulled out. This will inevitably leave pieces still in the soil, and even the smallest rhizomatous section can result in regrowth.
For the best success, digging out the roots is required. You'll need to dig at least six to nine inches into the soil.
You should slowly, gently and methodically sift out any root sections, and all parts of the plant should be put into sealed general waste. If it's added to compost heaps or bins, it could grow back once the compost is applied.
Creeping bellflower roots can also become entangled with the roots of other nearby plants. You may have to sacrifice other species while you're working to rid your garden of this weed.
If you have a prized plant you want to try saving, it would be best to remove it and carefully try to separate it from the roots of the bellflower. The roots should then be washed off, and the plant should be kept in a pot to make sure that no creeping bellflower growth reappears.
Another organic method for removal of creeping bellflower is to cover the plants to deprive them of light. This is only practical if the flowers are growing in small patches.
You can use newspapers, cardboard or black plastic which is then covered over with soil or heavy mulch.
This method isn't foolproof as sometimes the roots will lie in a dormant state and new growth could appear the following season.
Chemical removal is best kept as a last resort. Not only are herbicides less environmentally friendly and risky for use around children and pets, but they don't always have the best success rate.
If the plant has invaded your patio or paved areas in your garden, it could be worth adopting this method as it won't be possible to dig up the roots.
Widely available broadleaf herbicides and defoliants such as 2,4-D have been proven ineffective at dealing with creeping bellflower. Limited success has been shown, however, with those that contain the active ingredient glyphosate, like Roundup®.
Applying the treatment directly with a sponge directly can prevent it from coming into contact with other nearby broadleaf species. Best success, however, will occur if it's sprayed generously on the plant.
Treatments should be applied in late spring or early fall and, ideally, temperatures should be 60 and 85 degrees Fahrenheit. You want to ensure there isn't any rain forecast for at least a couple of days after the treatment, too.
If the plants have spread to your lawn, you could apply a herbicide containing the active ingredient triclopyr as this won't damage the grass
Weekly reapplications for several weeks are often recommended.
Mowing and Deadheading
Rigorous hand pulling, mowing, and deadheading won't eradicate the species, but it'll prevent reseeding and can help control spread somewhat.