I have a beech hedge which I planted bareroot 3-4 yrs ago and it has never properly established. Each year in spring time the buds/leaves burst and flourish out and it seems like it is doing well, but then by around mid June, it seems to stop growing. Some plants die, some turn yellow, some wither away and it generally looks unhealthy. I do water it if we have any dry spells but doesn’t seem to make any difference. I have lost about 20% of the plants each year and have been replacing them each winter but I need to find out what the problem is. How can I find out what the problem is?