Posted: 03/06/2016 at 21:36
If you think it might be an invasive grass such as couch grass:
Then unless you dug out every single piece of root it will come back. If it is that, let it grow and spray with a glyphosate based weedkiller and let it go completely brown before removing otherwise the roots won't be killed.
If it was just normal grasses, then you could plant up with lots of summer bedding plants which will shade out any grass growth and just weed out any which appears between them. Keep it clear over the winter and then you can plant up with more permanent perennials and shrubs next spring.