Creeping Charlie

The creeping charlie around Chicago is flowering. Shown above is a thick infestation, crushing a super-neglected lawn. Once it's in a lawn like this, every time you mow, the creeping charlie will pop up faster than the grass, weakening said grass and strengthening said creeping charlie.

Creeping Charlie aka Ground Ivy

Glechoma hederacea. Eurasian invasive.  Is in the mint family. When I lived in Michigan my lawn was completely covered by this plant. When I would try to make a bed it would creep in soooo fast.  It expands via rhizomes, and if you pull it and any of it stays in the soil, it will regenerate. Persistent pulling can be effective in a small area.   Apparently a borax spray kills it easily -- look into this if you need to control it.