How big of a patch are we talking about? When I have waited too long and cut the new growth, it looks cut and has a brown edge. But I have carefully, with garden shears, cut the old growth without touching the new stuff. Do that a couple of times and you'll remember to catch it early next time. :)

It's a pretty big patch, but doable. Thanks!

You could have just set the mower height higher, and mowed it anyway. I have done that before, and it grew above my mowing...

Is it too late now? Just bought a mower on Saturday.

I have no idea, how tall yours is... thus, I can't tell. :(