The hedges are compact borders, consisting of plants placed very close together, so that the branches and the foliage interpenetrate, so as to make more plants appear as a single entity, which is exploited as a dividing wall, as a border, as a screen against the scorching sun, or simply as a boundary between the flowerbeds.
There are different types of hedges, as different are the plants used to make hedges; there are compact hedges of evergreen plants, deciduous hedges, coniferous hedges; each hedge also has different sizes: there are small boxwoods that, over the years, do not exceed 30-35 cm in height; but also large tuje, which can easily reach 5-6 meters.
The choice of the hedge depends on the needs we have, on our plant preferences and on the space that the hedge can or must occupy.
Prune the evergreen hedges
Evergreen plants that are most often used as hedges are some varieties of shrubs, often with minute or medium-sized foliage; the small leaves in fact make it easier to maintain a compact hedge over time.
The most used plants are boxwood, privet, viburnum, cotoneaster, pyracantha, evergreen prunus, laurus; there are hundreds of varieties used, and periodically some plants fall into disuse, while others come back into fashion, or some are introduced as hedge plants.
What the evergreen plants used for hedges have in common is their vigor and rusticity: they use shrubs that have no particular cultivation problems, that have a fairly rapid development and do not require great care.
The vigor of these plants is also manifested when we have to prune them: generally the hedges of evergreen plants need repeated pruning during the year, in order to keep them dense and compact.
Prune the hedges of vines
Often as a hedge, especially if it is a wall of division between several properties, we use creepers, evergreens or even deciduous leaves; the most used are trachelospermum, climbing cotoneaster, ivy of various types. Even creepers have a very vigorous and rapid development, especially if they are evergreen essences; therefore also in this case the pruning will be repeated throughout the year. It begins with a vigorous pruning in late winter or early spring, and then other prunings are repeated as soon as the development of the outermost branches becomes messy and excessively long. The last pruning is done in late summer or early autumn.
Prune the hedges of flowering plants
There are many flowering plants that are used as hedges, from forsythia to jasmine, from wisteria to some varieties of hiperico, or even roses. Given that we generally choose a flowering plant to enjoy the flowers, in fact, it is good to practice pruning avoiding to remove buds not yet bloomed. In the case of plants that also produce berries, we must remember that to obtain many colored berries we will have to allow the plant to produce many flowers.
So in the case of plants that bloom on new branches we practice vigorous pruning at the end of winter, and then repeat the operation a few weeks after flowering. In the case instead of plants that bloom on old wood, we wait to prune them when they have already bloomed, because a drastic pruning before flowering could take away even most of the buds.
Prune the coniferous hedges
Conifers are very particular plants, if we prune the apex of a conifer, it will stop its development in height, tending to develop only in width; for this reason we avoid pruning the high part of the conifer hedges until they have reached the height we want for our hedge; these plants do not need many pruning during the year, above all because many of the species of conifers used for hedges are of rather compact varieties.
The problematic hedges
In general, as well as for the type of plants used, the hedges can also be divided into two large groups: the formal hedges, or those with a well-defined and clear form; and informal hedges, or those with a freer development and without regulations.
If we want to obtain a dense, compact and healthy formal hedge we will have to remember to start pruning as soon as the plants are planted, in this way we will begin to direct the initial development of the plants already in the way we want, also promoting the production of many small twigs, which give the hedge a dense and compact appearance. If we waited a long time to prune our formal hedge we could favor an incorrect development of the plants that make up the hedge, which would tend to empty the foliage in the most internal areas of the hedge, and to produce very thin branches in the external areas: in this way, pruning would do nothing but leave the hedge with gaps in the vegetation, difficult to fill. This occurs because generally in areas where the foliage of a plant does not receive light it tends to stop producing foliage.
If instead we practice light and frequent pruning we allow sunlight to penetrate even the most internal areas of the hedge, which will continue to produce small branches even in the most internal branches.
Informal hedges can generally require less care; remember, however, that even in this case, if we let the plants that make up the hedge develop without a brake, they will tend to empty themselves in the central and low areas; so also in this case periodic pruning allows us to have a compact, impenetrable, and dense hedge.