For the past 6/7 years I’ve battled this weed that keeps popping right back up every year. Finally this year I dug up the whole section of the garden it had taken over and found very large white roots hidden deep underneath the topsoil, growing into the gravel beneath it. I’ve tried to identify it but I’m not certain–the leaves very much look like Colt’s Foot but I’ve never seen any of the yellow flowers Colt’s Foot is supposed to have in the spring. I’m attaching a picture of the largest root formation I found, with some of the leaves still attached. Can you help me identify it? Thank you!
Thank you for your question and picture.
We are often asked to identify this weed and I have included information that was previously posted to this website. Your weed is most likely creeping European bellflower, Campanula rapunculoides. It spreads via its rhizomes and readily resprouts from these rhizomes and its perennial roots when dug up incompletely. If you would let it grow it would eventually produce quite showy bell- like blue flowers for which it was once introduced from Europe as an ornamental.
You will find more information about this invasive plant in this previous post on our website
This link to an article by Liz Primeau provides excellent pictures of its root system https://lizprimeau.com/creeping-bellflower-beautiful-but-evil/ very similar to the picture you provided to us.
To get rid of it, if possible at all, certainly needs persistence and vigilance over several years. Never let it bloom and set seed. Get at it as soon as its leaves emerge in spring and keep monitoring the sites where it grows throughout the entire growing season. An alternative to digging is to regularly cut the stems at soil level as soon as new leaves emerge. This should eventually deplete the roots of nutrients and their ability to send out new shoots. Do not put root and shoot fragments in your garden compost as they might regrow.