In the name of beauty, convenience, or fear of missing out, many gardeners have at some point unknowingly cultivated an invasive plant. Sometimes, we’re attracted to a vibrant foundation plant or the allure of brilliant fall colors. Other times, we want to avoid disappointing a neighbor who insists on sharing their rapidly growing perennials with us. With creeping bellflower (Campanula rapunculoides), observers are captivated by its 2- to 3-foot spikes of blue-purple, bell-shaped flowers.
However, the admiration typically stops there — creeping bellflower is one of those breathtaking flowers you’ll soon regret having in your yard and garden. These plants — invasive in parts of the US and Canada — have roots that can strangle neighboring plants, which, for most of us, is reason enough to consider creeping bellflower one of the invasive plants you should never grow. Once they take root in your yard, removing them can be an arduous task. These plants have developed resistance to certain herbicides, can easily self-seed, and even the smallest root fragment can sprout into a new plant. To eliminate them, gardeners must painstakingly uproot entire plants.
Some gardeners inadvertently add this flower to their yards as it is sometimes included in wildflower seed mixes. Gardeners forewarned of this can avoid purchasing nursery-grown plants or accepting giveaways from friends or neighbors. But unless you know what to look for, you may mistakenly think you’re acquiring a harmless lookalike, when in fact you’re about to purchase an invasive species.
How to identify creeping bellflower and better alternatives for the garden
If you’ve encountered a patch of flowers and want to determine if they are the invasive species in question, examine the stems and flowers. Creeping bellflower blooms are purplish-blue and bell-shaped, hanging on flower spikes, with blooms opening from bottom to top. The plant begins as a low-growing mound with heart-shaped leaves, but as the flower stalk grows, the leaves higher on the plant become more lance-shaped. Two more distinguishing features are the leaves, which have toothed edges and hairy undersides.
For those wishing to avoid adding creeping bellflower to their garden, there are many alternative plants that don’t possess the invasive’s unfriendly traits. Among the blue-flowered alternatives, there are many US native penstemons, beautiful long-blooming perennial plants you can easily grow from seed. Another option with blue blooms is blue mirror delphinium (Delphinium grandiflorum ‘Blue Mirror’), a non-native ornamental that is not invasive. Or, if you’re seeking a plant with striking flower spikes, consider blazing star (Liatris spicata), a favorite of hummingbirds.
