What type of tree did you plant? Looks like a Silver Maple maybe.
What killed the first tree?
If it were me, I would not have planted anything in the old hole. If it was a disease or another problem leading to its death, that issue is still in the soil. It could kill this tree as well.
It is just a belief of mine that I never plant trees in the summer. I plant in early spring or in mid fall.
Yours could be suffering from too much heat and improper watering. But if that's the case, these problems should clear once it is fully established.
