Creeping Bellflower: (Ob)Noxious Weeds in Wildwood

Many people assume creeping bellflower (Campanula rapunculoides) is a garden-worthy perennial – it looks like a harmless, pretty garden bluebell, with its low-growing foliage sprouting tall flowering spikes in the summer. Sometimes confused with the native harebell (Campanula rotundifolia), creeping bellflower was actually introduced to North America as an ornamental garden plant from Europe. Due to its aggressive and difficult- to-control spread into the surrounding landscapes, it now finds itself on Alberta’s “Noxious Weed” list.

Concerned Wildwood residents have noticed creeping bellflowers creeping into more and more yards around Wildwood. If you have mistakenly allowed creeping bellflower to grow in your garden, please note that noxious weeds must be controlled (i.e. you can’t let them go to seed or spread) as per the Alberta Weed Control Act. These invasive alien species are a threat to natural ecosystems and to agricultural crops. Creeping bellflower is perennial, fast-growing, deep-rooting and nutrient-sucking. They spread by rhizomes (even the tiniest root fragment can grow into a new plant) and seeds (each stem can produce up to 15 000 seeds!).

What You Can Do

  • Act now! Check regularly for creeping bellflower on your property (gardens, yards and alleyways) and remove any plants immediately to prevent further spreading. It is easier to control one or two new plants, rather than a patch of established bellflowers.
  • Nip it in the bud. Hand-pulling or cutting and disposing of the flower spikes pre-bloom can prevent seed production, but will not eradicate it.
  • Dig it out. Digging out as much of the root system as possible can be successful, but will require multiple years of effort. The rhizomes can be found as much as 6 inches below ground and resemble the shape of a carrot but are a pale beige colour.
  • Bag and dump. Do not compost the flowering stems or roots as this will spread the weed. Bag any flowers, seed heads and plant parts, and throw it in the garbage bin.
  • Chemical options: The creeping bellflower is resistant to 2,4-D. Glyphosate is effective for spot applications and dicamba can be used for broadcast application such as lawns. Consult your local Certified Pesticide Dispenser for more information.
  • Contamination: It is best to throw out any garden plants infested with
    creeping bellflower. If it is a prized, irreplaceable plant, you can try
    washing all the soil off the roots and removing all the creeping
    bellflower roots. Keep it in a pot or plant it in an isolated location until
    you can be sure the weed is eradicated. Spring or fall is the best time to do this bare-rooting operation. Cut the plants back before replanting them as they will not have enough roots to support the top growth.
  • Alternatives to creeping bellflower: Consider other ornamental garden selections to replace your creeping bellflower (e.g. native bellflowers, native and ornamental beardstongues, blue mirror delphinium).

Let’s keep Wildwood beautiful and noxious weed-free!

Sources:

  • www.calgary.ca/CSPS/Parks/Pages/Planning-and-Operations/Pest-Management/Creeping-bellflower.aspx
  • www.invasiveplants.ab.ca/factsheets/FS-CreepingBellflower.pdf
  • www.iucn.org/about/union/secretariat/offices/iucnmed/iucn_med_programme/species/invasive_species/

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