I have 2 Red Robins which are about 6 or 7 feet tall, and the leaves are turning from red to green, is this due to the heatwave and is there anything that needs to be done or will it sort itself out?
It's normal. The new foliage starts red and eventually turns green. If you trim them a bit they will put on fresh red foliage which is why this plant makes such an interesting hedge.
I agree obelixx. I have 3 Red Robins & this happens every year. They are very easy to care for.