My husband and I recently bought a home with a beautiful flower bed in the backyard. However, we found out that it’s been overrun by goutweed. I’ve done a lot of research online and have learned that it’s extremely difficult to get rid of. The flower bed is completely full of it so it would be almost impossible to go through and attempt to pick it all out and solarize it…plus, it would end up killing all the other flowers around it. We’re wondering if it may just be a better choice to tear up the bed, lay down some kind of ground cover and build a raised bed over it, essentially just covering up the ground completely? We currently live in Halifax, Nova Scotia. The bed gets a fair amount of morning and midday sunlight.
Thank you for your inquiry and sorry to hear that you have goutweed.
Long touted for its ability to thrive in areas where little else will set foot, goutweed, also called Bishop’s weed (Aegopodium podagraria) is considered by many as the ultimate low-maintenance ground cover for shade, partial shade and full sun. That’s because, once established, this low-growing perennial with its all-green or variegated foliage spreads vigorously by vegetative means, extending its rhizome system to form large colonies without any encouragement. Therein lies the problem.
Eradicating goutweed takes time and patience. In order to get rid of it properly, you need to follow its root and completely unearth it. This is easier after a good rain. Please note that just 5mm of root left will create a new plant. Of course this job is easier if you do not have other plants in the area. However, because you have perennials, it may be advisable to dig them up and clean/eliminate any of the goutweed roots. You will need to dig down about 2 feet then sift the soil to remove all the roots and rhizomes. Rhizomes should be bagged and disposed of to prevent reestablishment.
Frequent mowing at short heights can control or slow the spread of goutweed but will not make it disappear. However, not allowing the goutweed to bloom will stop future plants from germinating. Doing this early in the year just after the plant has fully leafed out, and covering the entire colony with black plastic sheeting afterwards, is a great way to exhaust its energy reserves.
Please see attached for a couple of interesting links.
Good luck battling the goutweed!
https://savvygardening.com/goutweed/
http://www.ecosystemgardening.com/kill-the-bishops-weed.html