Creeping charlie
Problematic
Glechoma hederacea
This weed can be hard to detect at first because it grows so close to the ground. Most commonly found in lawns, you may not know it’s there until you see a cast of tiny purple/blue flowers early in spring.
A member of the mint family, creeping charlie roots itself into the ground at every leaf node (where the leaf comes out of the stem). This is how they spread and creep. They prefer poor soil and are especially aggressive in damp, shady areas in lawns. The leaves have a minty but pungent aroma when crushed. In large quantities, this plant is highly toxic to horses.
While ripping out long strands of creeping charlie is strangely satisfying, getting rid of it is difficult. There is evidence that creeping charlie is resistant to broadleaf herbicides. A better strategy for control is to help your grass compete. Set your lawn mower blade at 3” and use a mulching lawnmower. Water your lawn deeply and infrequently. Fertilizing your lawn with compost may help. Overseed your lawn if needed.
Sources:
http://msue.anr.msu.edu/resources/ground-ivy-control-for-home-lawns