This weekly Wednesday post is from PEIISC member and Stewardship Coordinator at Island Nature Trust, Julie-Lynn Zahavich. This week, Julie-Lynn will share her experience with a common horticultural invasive, Creeping Bellflower.
Creeping Bellflower (Campanula rapunculoides) is an ornamental plant that was imported from Europe. It has heart-shaped leaves that grow around the base of the plant and longer, lance-shaped leaves that grow alternately along the flowering stem. Blue, bell-shaped flowers bloom along the flowering stem from July to September. The plant can reach 1m tall and spreads underground by rhizome, and by seed. It will tolerate a range of growing conditions, including full sun or full shade.
It’s a sneaky plant. The beautiful, trumpet-like flowers tempt many gardeners into planting Creeping Bellflower in their flowerbeds. I have noted several patches of it growing in Charlottetown gardens and lawns. Gardeners may find that the plant “behaves” for a short time but, like many invasives, will slowly creep up on your other plants (Hmmm, I wonder if that’s how it got its name) and take over an area.
It is very difficult to eradicate. Some people refer to Creeping Bellflower as “the zombie weed” (http://www.salisburygreenhouse.com/creeping-bellflower/), because of its incredible ability to spread and seemingly come back from the dead. Creeping Bellflower produces thousands of seeds per year. Removing seed heads can help reduce the spread, but will not get rid of the plant. Digging the plant can help but will take persistence, because any small piece of rhizome left in the soil can give rise to a new plant.
This past summer, we found Creeping Bellflower growing in a hedgerow on an Island Nature Trust property. The population was relatively small, but was beginning to dominate parts of the hedgerow understory. At Island Nature Trust (INT), we manage our 3,700+ acres of protected natural area on PEI to maintain ecological integrity and function. This includes removal of invasive species, which can reduce biodiversity and compromise an ecosystem’s ability to function.
Summer is an insanely busy time for us at INT so by the time we had a chance to address the Creeping Bellflower on this property most plants had already gone to seed. We removed the flowering stems to reduce the spread by seed and limit the energy being delivered to and stored in the plant’s rhizomes. These efforts won’t eliminate the population, but they are an attempt to control it temporarily until we can return next summer.
Although, at INT, we refrain from using chemicals on our properties, herbicides would likely be ineffective. Creeping Bellflower is tolerant to many herbicides, including glysophate (the active ingredient in Roundup). Mechanical removal seems to be the only feasible option for Creeping Bellflower removal.
So as we draw up our land management plans for next summer, we know we will be heading back to this property to at least remove seeds from the Creeping Bellflower. This may be all we have the resources to do as our time and efforts are usually spread thin during the summer months. There is a lesson here though: even if we can’t completely eradicate an invasive population it is still worthwhile to attempt to control it. If we let the Creeping Bellflower go, we would have even more work on our hands and so would the neighbours!