I think it is more likely you have under watered it. Newly planted trees require a huge amount of water and if you planted just before or during the drought the tree will be extremely stressed. Really soak the ground round it and them water regularly.

Thank you...I planted it about 4 weeks ago and watered it morning and evening for the first two weeks, the ground around it does feel damp! Should I carry on with twice a day?

No. Leave the hose running on a trickle at the base overnight. Then wait a week and unless we're having torrential rain, give it at least a couple of gallons, or leave the hose running again. Carry on in this way until we get to autumn, and only stop then if the weather is cool and damp. You will need to make sure it gets a couple of gallons a week minimum all next summer too. The first 2 years are critical for water with new trees.
The worst thing you can do is give a little water twice a day - it doesn't penetrate to the roots, nor to the soil surrounding the roots, and encourages surface rooting of the tree, which is the last thing you want.

Agreed Bamboo a lot of water less often!

Thank you both so much I will try that tonight!

Mine has same problem. It was planted 4 days ago
I watered it and then 2 days ago we had a storm. The soul seems pretty moist. Do you think it's over watered. Leaves also look very limp.

Thanks

No, the answer is the same as already given to San.