You won't "hurt" the grass, but they may not look very good.

"they may not look very good" is an understatement.

The blade of foliage will have squared-off and probably browned edges at the end, and will look terrible.

Depending upon the type of grass, you may also delay, diminish or completely abort blooming.

The only solution is to move them.

okay thanks for your help!!!

Or replace them with a smaller-growing grass.

I have read that large ornamental grass can be split in the off-season to make them smaller the following summer. This may be an option for people who have large-growing grasses and want them to be smaller. But it takes some patience.

^^^ But they will only be smaller for a single season. The next year they will be up to full size again.