Boxwood, like many other shrubs that make good hedges, needs to be pruned to keep its good look.
Boxwoods (Buxus) are great shrubs that are frequently used in formal designs to edge beds as well as an evergreen accent plant. Although the shrub can be left to its own devices as far as growth is concerned, in many situations it needs to be trimmed and pruned.
Formal gardens require that the hedging material is crisp and sharp. To achieve this look you need to prune the boxwood regularly. The first new growth starts just before the flowers arrive, but the flowers are rarely noticed. Assuming that the hedge is at the height your design needs, you should keep the new growth trimmed back so that it doesn’t look untidy. This is best done with a hedge clipper. If you are not good at cutting straight lines, place a stake at several intervals and mark the stake with the hedge height. Run a string between the stakes and use this as a guide for cutting. After a while you will be able to trim the boxwood without using stakes. You will probably need to trim wayward growth several times over the summer to maintain a good shape.
For boxwoods that are still growing into their final height, you will want to let the new growth remain. Trim the areas that you do not want to grow such as the sides. Also remember to make the top slightly narrower than the base. This is particularly important to do if the hedge is large. Too often a hedge is left with a narrow bottom, and the base of the hedge gets no light. Consequently there is no new growth in that area and the base becomes unattractive and brown. Shaping the hedge with a wider base will avoid this problem. The shape however, does not have to be pronounced as in a triangle.
Overgrown boxwoods need slightly more drastic treatment. The boxwood regenerates well so reducing the boxwood to the required height is possible to do in one session. The shrubs however will look a mess for a season or two before recovering! Even more drastic is a method that sounds overboard, but has been known to work. The whole shrub is reduced to a height of about two feet. You will probably need a chainsaw to do this as the older stems are tough and thick. New growth will become evident on the bush very quickly, but it will take time for a good form to be assumed. These methods are generally used in an attempt to save old boxwoods which have become very overgrown after decades of growth and improper or no pruning.
A note of caution here: The expert advice that I have come across is very divided on this second method and although it was common decades ago, some warn that drastic cutting can expose areas that retain water, and thus encourage disease and rotting. Others proclaim that new growth is more vigorous and a healthier bush results.
Boxwoods that need a lot of pruning to stay the size that you want probably should be replaced with a smaller variety. There are small boxwoods that stay under two feet and taller ones that grow to ten or fifteen feet. Getting the right one will go a long way to ease the maintenance hassles.
