I have a golden Leyandii hedge about 20 yrs old it has grown very wide over a path on the sunny side Last year I cut back the height of it to about six foot or so Now I would like to reduce the width of it I have seen a few hedges which have been cut back to the main trunk Would it be possible to do this to my trees given their age and if so whats the best time to do it the hedge is well furnished with greenery down to ground level any advice would be welcome