Think we could do with more info please....aspect, conditions, is it a recent thing it's not looking well? A photo would be extremely helpful.

Assuming that there is nothing drastically wrong (more info would be good of course) with the plant you could just feed with a slow release fertiliser and do the following operation.

It may be due for renovation and can be done any time now. This can be used as a good excuse to do any major re-shaping too. Cut hard back all over to stems up to the thickness of a marker pen. It will re-shoot well from this. Apply a general slow release feed around the base such as Vitax Q4 or similar.

Watch out for bird nests tho ;-)

Good point Sid.