re: Virginia Buttonweed will destroy your lawn.

Virginia buttonweed is sneaky AF. It really doesn't look that bad IMO, so can be easy for someone to ignore, but it is very aggressive and will completely demolish your turf grass. It had taken over a decent patch of my back yard about a year ago. One round of Celsius zapped it, but that part of the yard was basically dead for the remainder of the year. I think it has almost fully recovered though.

Right now, dallisgrass and nutsedge are my two biggest headaches.