I have a Red drummond maple tree been planted about 8 months. I planted it when it had no leaves. It sprouted really nice when spring came around. The leaves looked really nice and green. Well summer came and I got the burnt leaf tips now. I live in south Texas so it's HOT. The nursery said it was from over watering. I was using a tree gator daily almost. Does this look like over watering? Or disease or heat??

The tree is pretty much in the middle of the yard so gets direct sun all day.