Lawns of Rome
The concept of "lawns" as we know them didn't exist this far back in antiquity. There were fields for crops and fields of naturally growing grass where, if people did anything besides pass through them, they might train for war, or simply war. Many Roman towns would feature a Campus Martius or "Field of Mars" used as military parade grounds, for example.
Scythes certainly existed, but as farm implements. It was not a display of wealth (as with English aristocrats over a millennia hence) to show you could own arable land and pay workers to mow down the grass and do nothing practical with it.
Citizens of Rome did enjoy sports, but it's not as though their pasttimes were croquet or football -- a hard-packed patch of dirt was perfectly fine without thick, rich, vividly green turf as, again, became popular with the English many centuries later, particularly the emerging middle-class of Victorian times.
Gardens, however, were a whole other matter. But that's a story for another time...