每日吃瓜

Hello folks,
Can someone help me!? I bought this lovely Prunus last spring at Lodder 每日吃瓜, and it has seen some pretty hot days. I have triend to keep it out of the bruning sun (have forgotten it a few times). The leaves are turning black at the edges and it looks ugly.. someone know what is going on, is it the heat and me paying not enough attention?
Thanks!

This is classic lack of water. I am watering twice a day at the moment, I assume it is outside in semi shade, if you cannot water more than once a day then stand it in a tray with gravel and fill with water this will help. The damaged leaves can be removed.