I have a griselinia hedge that is about 40 years old. But in the last couple of years it has developed dead patches, whole plants just died. I would thin them out and the two plants either side would fill in the gap. But at one end of the hedge, at the entrance to the house, the rightmost plant is wilting and the next plant to the left is dead. So I can’t thin these two plants because there is no plant to the right to fill the gap. I have never encountered wilting before and am wondering should I remove both plants completely and replace with new plants. This will leave a large gap at the front of the house while the new plants grow. Any idea why the griselinia could wilt like that?Also I have a very large griselinia at the back of the house. It is 25 yards long and 8 foot high and up to 6 foot in width. It is becoming very dificult to trim, especially as it is so wide. Could you advise on how to prune such a huge hedge. Several of my neighbours have used a chainsaw to take a foot off the top, no sure if this is a good idea, but theirs seemed to grow back within a year. Or, how does one trim the sides to make it narrower and more maneagable?
You can split a hedge by cutting off the sides, front and back, to a width of perhaps 50cm. It looks unsightly for a while but soon re-sprouts. Griselinia can be cut back into old wood.
Do this in spring and feed afterwards with general fertiliser.