Poorly unknown shrub
We recently moved house (March last year) and I've been trying to get to know my new garden. One adopted plant is a large shrub about 2.5m tall and 2m wide which had beautiful white sprigs of flowers on through (I think the early summer?). Unfortunately it's now showing signs of disease, has dropped all it's lower leaves and I'm not quite sure how to help it! The leaves are getting black spots then turning yellow then falling off. I've tried to attach a photo but as this is my first post in the Forum, now quite sure of it's worked! Any guidance on potential shrub care would be gratefully received. At the minute I've just pulled the diseased leaves off to buy some time. Any thoughts?