I have two Choisya Aztec Pearl in my back garden, and both are dropping lots of leaves and looking poorly despite having buds. I have only had the garden just over a year and don't remember them looking this bad last spring. Could it be the cold winter/spring so far, or something else?
I also have two Myrtle Communis which are also looking a bit poorly (brown patches on leaves etc). These usually do well (my house is called Myrtle Cottage and has been for 150 years - suspect the Myrtle in the front garden has been there a while and was huge (20 feet tall) when we moved in). Its against a sunny south facing wall and we are by the sea. Although I would prefer it was a bit smaller, I don't want it to die!