Q.Thick Grass in Lawn With Very Heavy, Thick White Root System
What is the grass called that is spreading all over the lawn and creeping into flower beds? It has wide blades and a very heavy, thick white root system that I can’t seem to get rid of. I’ve even applied Round-up, which slowed it down but didn’t get rid of it. I live in Iowa. It went into my creeping phlox, and I couldn’t keep it pulled out–eventually it took over. I want to kill it out so I can start over again.

Certified GKH Gardening Expert
It sounds like you have quack grass. This article will help:
https://www.gardeningknowhow.com/plant-problems/weeds/killing-quack-grass.htm