I planted 80m of potted green holly Sept 2010 to form hedge. well prepared trench compost and mosspeat, with leaky hose at back, used initially until plants settled in. did very well, lots of new growth in 2011. black leaves and branches appearing this winter in some plants with leaf loss.sheltered site, east facing beside old ditch. any advice
The plants are likely to sprout again but may be affected again. Spraying is of limited effect but might help if you try a copper spray such as Bordeau mixture.