Cherry Tree Dying

by Barry
(Knoxville, Tennessee)

I have about 6 cherry trees (pink) planted along a drive by my house. They are about 8 years old. All of them seem to be thriving but within the last 3 months, one looks as if it is beginning to die. A couple of small limbs are dead. Leaves are yellowing and turning up. I have fertilized it, and I water it 2-3 times weekly. I have sprayed it for insects. Do you have any other ideas I might try? Thanks.