help needed hedge issues (brown disease)
 

im new to gardening in fact if friends new i joined a forum they'd laugh.. anyway i put a hedge in about a year ago cost a fortune its a azara microphylla variegate i think this from looking at pictures on the web green/white small leaves ...the problem is its leaves have started turning brown/black but only at the front near the road and its spreading, ive been told its due to the excess rain we've had is this likely do they change colour in winter or is it diseased as to me it looks like the leaves are drying out and dying .....all advice welcome cheers