Some neighbours tried to clear dog strangling vine and thistles from their small, contained front yard last fall but failed ( no digging), now there is a forest about 2 feet high and growing! What advice can I give them?
Thanks for contacting Toronto Master Gardeners. These are two invasive weeds and it may take several seasons to get them under control. The most important thing is to get at them early in the season and deplete their nutrient system. Since they are both established it is best not to pull them out as it encourages root growth. Cut the stem of a thistle at its base before the flower buds open. Cut dog strangling vine just below soil level. Don’t let either of the plants go to seed.
The other thing you can do is to make the area less inviting. Make the soil more fertile and put in grass or other ground covers that will complete the weeds. For more information refer to the following Toronto Master Gardener posts:
https://www.torontomastergardeners.ca/askagardener/dog-strangle-vine/
https://www.torontomastergardeners.ca/askagardener/dog-strangling-vine/
And this website:
https://www.canadagardener.com/how-to-control-canada-thistle/