Q.invasive thyme
invasive thyme has taken over the yard of my friend. What can we do?

Certified GKH Gardening Expert
Other than removing by hand, the best way to remove invasive thyme is using herbicides. Choose a broadleaf herbicide, since these will kill the thyme but not the grass. See this article to learn about what is available:
http://extension.illinois.edu/lawntalk/weeds/broadleaf_weed_problems_in_lawns.cfm
Organic alternatives are discussed in this article:
http://ucnfanews.ucanr.edu/Articles/Feature_Stories/Organic_Herbicdes_-_Do_They_Work/
Some other strategies for removing invasive plants are discussed here:
https://www.gardeningknowhow.com/edible/herbs/mint/invasive-mint-how-to-kill-mint-plants.htm
Thyme is in the mint family, so the advice should apply to it as well.