Pruning North Coast Hedges
There are two main types of hedges. Informal ones allow plants to grow to their normal height and develop their natural shape. They need very little maintenance after they are full grown. Formal hedges, on the other hand, are clipped to perfect shapes, and if they are to look attractive they must be trimmed frequently and meticulously.
The future good looks of all hedges depend upon their care and pruning when young. If they are rapidly-growing plants they will tend to become tall, without lower branches, unless cut back frequently during their first couple of years. You cannot, in later years, go back and fill in missing lower branches. So you must be hard-hearted and prune early growth. This does not apply to slow-growing shrubs like box. Fast-growing shrubs, like privet, honeysuckle and barberry, should be cut back at planting time almost to the ground. Leave only 3 or 4 buds on each stem. Cut back again, about a third of the height, each time the stems grow a foot. Continue the process for at least two years or until the hedge is the height and denseness that you wish.
If you are dealing with a hedge that is to be clipped into a formal shape, guide its growth through the early years of pruning so that it is wider at the base than at the top. The main reason for this narrower top is to keep it from shading the lower branches and keeping vital sunshine from their foliage. This will prevent those holes in the bottom of hedges. Also, if you live in higher elevations and have snow, it can slide off more easily, doing less damage.
Pruning Tools and Techniques
The easiest and most pleasant way to trim a shaped hedge is with a powered hedge trimmer. Be sure the one you use has safety features. To cut a truly straight edge, do not trust your eye to guide you or you will have wobbly, wavy lines. Place stakes, with strings as markers. If the hedge is against a building, particularly if the structure has a strong horizontal accent, keep the top of the hedge on the same horizontal plane as the building, even if the ground slopes. If there is a great deal of elevation change, step down with the hedge top so it complements the building, do not follow the ground contour.
Time and frequency of pruning depend upon the kind of shrub you are using, and how the hedge is to be trained. A formally shaped, rapidly growing hedge, such as privet, needs several trimmings a year. Most other deciduous sorts need at least two. One of the trimmings can be made in late winter or early spring while the plants are still dormant, leafless, and easy to cut accurately. The other can be when the new growth is at its peak. Flowering hedges are not pruned until after the bloom.