Posted: 27/06/2015 at 20:14
You could look on this as a long term project and replace one boundary every 5 years. That would give each new hedge time to grow. But you will always have that 'loss' of about 1m for the width of the hedge and the problem of dry soil at the border.
I have leylandii hedge on 2 sides of my garden about 6-7 ft tall. It gets cut once a year in Oct/Nov time and still stays neat all year.