The key to maintaining a perfectly dense privacy hedge is consistent pruning on the sides. If the hedge is allowed to grow large and leggy, then pruned hard, you will end up with gaps (in laurels and beech this can be corrected, but in conifers, it usually can’t). A quick, simple trim once per year on fast-growing varieties and once every 2 years on slow-growing varieties is all you need to keep your hedge full and dense. Pruning the top half of the privacy hedges a little slimmer than the bottom will keep the lower branches nice and full (see the diagram below).
For more information on how to get privacy trees as fast as possible, check out our page on fast-growing hedges.