JAPANESE MAPLES ARE BEST GROWN IN ZONE 4-9. THEY CAN HANDLE A LOW WINTER TEMPERATURE OF ABOUT MINUS 10. IF IT GETS CLOSE TO THIS TEMPERATUREOR LOWER, I WOULD COVER THE MAPLE FOR EXTRA PROTECTIONS. A NICE LAYER OF MULCH HELPS PROTECT THE ROOTS DURING THE COLD. ALSO IN COLDER CLIMATES TRY TO FERTILIZE ONLY ONCE IN THE SPRING, AND NOT LATE IN THE SEASON. THIS WILL HELP FROM HAVING TENDER GROWTH LATE IN THE SEASON, THAT CAN HAVE A HARD TIME WITH COLD TEMPS. 

IN HOT CLIMATES, THE BEST OPTION IS TO TRY AND INCORPORATE SOME SHADE WITH THE MAPLE. WHILE THEY CAN TAKE VERY HIGH TEMPERATURES, THEY PREFER SOME SHADE IN VERY HOT CLIMATES. MULCH ALSO HELPS IN THE SUMMER TIME, TO KEEP HEAT DOWN AROUND THE ROOTS, AND HOLD IN SOME MOISTURE.