By Pipey
United Kingdom 
I have a privet hedge which has been dieing over the past couple of seasons.
The branches look OK but the leaves are turning very dark brown and dieing off.
The hedge is approx 15m in length and the problem had started at one end of the hedge, a section about 1M in width and the whole height of 2.5M. This year the top of the hedge seems to be turning yellow to brown to about half way down it length and the infected area is expanding along the hedge from where it started.
Where the hedge end, there are areas of rough shrub along the boarded which also seem to heve become infected, almost the same aperence and results you would see if applying poison?
20 Mar, 2016
Firstly, although Ligustrum is evergreen, it does lose leaves at some time in the season. Next, it is also prone to lots of viruses which might not be treated with conventional fungicides ( a google search will confirm). Is the hedge on the edge of a council walkway, which could receive a dose of weedkiller? If only a small part of the hedge is dying which might be due to a soil-based virus, you could try replacing with new plants with the addition of Rootgrow in the planting holes. A mulch and a feed of the whole hedge could tip the balance for the rest of the hedge. Other than this information which you will possibly already know, then a re-think about a hedge of a totally different kind. Sorry, but this might not be of much help.
22 Mar, 2016