Young hawthorn tree struggling

I have a hawthorn tree that I planted about 3 months ago. It has seemed to be doing well and its branches have been growing. However, a couple of days ago a number of its leaves started turning yellow and some of them have dropped. We have not had a great deal of rain over the last week but plenty before that. I wonder whether anyone knows what could be distressing it?

 

The majority of hawthorns are very tough. I suspect your tree is just shedding some leaves because it's adapting to its new environment.

But most plants need extra watering for their first season after being planted out so don't just rely on rainfall. Give it plenty to drink during the summer and autumn, letting it dry out a bit in between waterings.

 

That's a relief - cheers for the advice Flinty!