Post category: Hedges and Screens
A hedge, or screen, is simply a line of trees or shrubs planted close together and trimmed to shape. Apart from providing shelter, privacy and boundaries, hedges can be used as a backdrop for the shape and colour of ornamental plants. A disadvantage is their tendency to draw moisture and nutrients from the surrounding soil. They cast shade too, and they often provide a haven for slugs and snails.
Small hedges can be very decorative
Hedges planted at close spacing thicken up more quickly, but cost a bit more. Competition between the plants at closer spacing means they are more easily kept to the desired size. Most common hedges, including evergreens, are best planted 60 centimetres apart. Smaller types, such as berberis and hawthorn, should be planted at 40 centimetres apart.
For a formal hedge, training should begin at planting, when the top 15 centimetres of the leading shoots are removed, which encourages the plants bush out lower down. Continue this tipping-back during the first two seasons and shorten strong side-shoots at the front and back of the hedge to keep the hedge narrow and encourage the plants to meet earlier.
Start clipping the sides first, to prevent the hedge becoming too wide. Clip the hedge to a wedge shape to let light get at the lower part. Otherwise the foliage dies and the bottom of the hedge goes bare.
Regular clipping follows on the initial training period. Begin regular clipping before a hedge has reached its desired final size. Never let a hedge get beyond its ideal height and then, too late, try to bring it under control, particularly with cypresses. Stop the plants 30 centimetres short of the ideal height and let them reach it over five or six years, thickening up in the process.
Clip hedges to be narrower at the top
For an informal hedge, such as forsythia or escallonia, and for tall screens, simply let the plants develop naturally for a couple of years. Then trim the sides with a secateurs, shortening all strong side-shoots. Flowering hedges should get this treatment after flowering. Avoid using hedge-clippers on informal hedges or screens if they are to have a natural informal appearance.
Another kind of informal hedge can be clipped to shape. In this case, the shape is informal, not the growth of the hedge. Unusual ‘cloud’ shapes, for instance, can be clipped into a hedge, even one that was formal to start with.
Badly overgrown hedges can be cut back part-way, even right back close to the ground, and they will sprout again. Hedges that have become too broad can have one side cut off. The second side can be cut off, two years later, if desired. April is the month for these operations.
Cypress hedges cannot be cut back in this way, as they do not regenerate from bare wood. Never cut them back beyond the green part of the shoots or they will stay bare.