Good Morning Everyone.
I got new lawn put in two years ago and it has this thick grass in it. last year we took them out and put new grass seeds in it place and this year they have spread even more places . please can someone advised me how to get rid of them.
It's couch grass. it spreads by roots. It's a difficult thing to remove as leaving just a small piece in the ground will grow a new plant. I don't remove it from my lawn, but to do so you need to lift the offending piece with a fork and then get every piece of root out. You'll see the roots easily as they are fleshy white roots several mm wide, you need to be careful getting them out as they break quite easily.
It will take time and effort so persistence pays in this case.
The problem with couch grass is that the roots spread horizontally rather than growing downwards - that's how it spreads, so wheedle it out sideways rather than digging down.