HELP! what is this??? and any ideas on how to treat?
thanks in advance for any help!
It looks like ground ivy to me. And it looks dense-I don't see any grass. Ground Ivy is hard to control. Possibly use Round-up then reseed the grass.
Probably is Ground Ivy, "Glechoma hederacea" and using any glyphosate product is overkill because they are very broad spectrum poisons that will kill everything they contact. Ground Ivy can be an indicator of a soil problem since they tend to want to grow. Generally Ground Ivy preferes a soil that is a bit too moist for most turf grasses and although they will grow in full sun they do prefer shady areas.
Since these seed prolifically you most likely will not ever be rid of it.
You can knock it back with a broad leaf herbicide, one containing 2,4-D or Dicamba. Then work on getting the grass thickened up.
2,4-D can vaporize and damage other nearby broadleaved plants. Ash trees and tomatoes are particularly sensitive, so be careful with 2,4-D. Dicamba is much less prone to releasing vapors.
You can indeed spray one of the broadleaf weed poisons that are creating many problems with our environment and then when these "weeds" reseed you can spray again. The long term solution is to look at the soil and correct any problems with that and get a good, healthy stand of turf grass growing so any "weeds" have little to no chance to grow.