What is wiping out my laurel hedge? Please help!

natashamcm764

Hi all, I have a laurel hedge. It's been in about 5 or 6 years and has always done well if a bit slow to really get going. Lately though, I've noticed a few unhealthy looking hedge plants and it seems to be spreading from one particulary unhealthy looking one. There's no really obvious signs of what is causing this, at least to my eyes. I've searched online for clues but to no avail. I've attached photos, please help! Natasha. 

Borderline

When they go yellow, there are mainly two reasons. Either roots sitting in compacted damp soil where water has damaged the roots over prolonged periods. Or, ironically not enough water. If you have seen them like that for a while, it's likely, the soil is very compacted and the roots are struggling to grow. Since the plants are in, I recommend you top dress like in the last photo with a thick layer of compost. Prune the shrubs back.