I’ve tried to dig out goutweed by the roots, but it keeps coming back. Any suggestions?
While goutweed can be a useful groundcover in areas where nothing else will grow, it can rapidly become an invasive and hard-to-get-of nuisance in the rest of the garden. It spreads by seeds and by underground rhizomes. Leaving even one small piece of root in the ground can result in it growing back.
One labour-intensive way to get rid of it is to hoe down or cut off all growing shoots every week or so until it no longer sends up growth. An alternative is to smother the plants – dig up as much as you can or just cut plants back down to the ground and
then cover the area with a thick layer of newspaper, cardboard or plastic.
If you are using newspaper or cardboard, cover this with a thick layer of mulch. The paper will break down so you can plant through it. I would not suggest using landscape cloth, as it does not break down, and planting in the area afterward will be difficult. If you use plastic, don’t cover with mulch – remove it in the spring after you are satisfied that nothing is sprouting under it.
Remember too not to put fresh roots in your home compost – let them dry out first. The city composting facilities should be hot enough to destroy the roots.