Groundcover out of control and smothering everything in sight!

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Q: On my property in Fanny Bay there is a section of groundcover that I had always thought was rather pretty. This year it is smothering everything in sight. After some research I found out is almost impossible to kill. Right now it is in two of my gardens.

Fortunately, both gardens have a cement sidewalk surrounding them that (I hope) is acting as a barrier between the dreaded species and the lawn. Is the only solution cutting it down then suffocating it over a period of a couple of years? Will we lose our hydrangeas, hostas, and other shrubs? I not want to use chemicals but certainly will if nothing else will eradicate the weed.

I will assume this is goutweed (Aegopodium podagraria), which spreads by roots and is dormant in winter. A quick way to identify goutweed is by scent – a broken piece of the plant smells like celery. Mulch the shrub bed using coarse wood chips, similar in texture to a tree that has been put through a wood chipper. Ensure the layer of mulch is 15- to 20-cm-deep (6- to 8-in.) and maintained year round. Coarse wood chips at this depth should not hinder your shrubbery but will still smother out the weed. Continually clip the weed tops. This combination will eventually weaken the root system.

For your lawn, ensure frequent close mowing and periodic overseeding with grass seed. Overseeding will thicken the existing grass and smother out the weed. Be patient and persistent – remember the weed did not appear overnight.

Systemic chemical (“Roundup/Wipeout”) will be absorbed into the weed roots to a certain length but not necessarily all the way. Chemicals may result in damaging other desirable plants and are not necessary for eradication.