Hi I'm new here and I’m looking for some advice I have about 54 Photinia planted in front of my house to form a low hedge height is about 4 foot the hedge has been established for 9 years and the top and sides are cut every year at the moment the top colour is bright red, and look just right but all is not well, the top has leaves and colour but the bottom two thirds of the shrubs have lost here leaves over the last few years and some of the lower branches are dead there is no filling out at the bottom. and no leaves. I have given fish blood and bone feed every autumn and it’s not helping. as an experiment I have this week lifted 4 of the shrubs dug deep and wide holes and put 4 new plants in fresh well-rotted compost. the old shrubs I removed did not have as big a root system on them as I would have expected. the hedge is open on both sides so good air and light all round. I have some brown spots but that’s not unusual. It will be very expensive to replace all the shrubs so that’s a last resort. Cn anyone suggest what I should or could try next.