If hedges are left untrimmed they will grow upwards and become relatively “leggy”, thin at the bottom and thicker towards the top. Care must be taken in the first few years to prune the plants so that they develop into a thick and effective hedge.
Many hedging plants will form very tall trees or shrubs if they are not regularly pruned. In general they will respond to the trimming of their vertical growth by producing side shoots. Sometimes it is necessary to trim verticals in order to promote bushy sideways growth even though vertical height is also required. It is all part of the process of establishing a well formed and effective hedge.
Most hedges should be trimmed to the desired shape before the hedge grows to the desired height. Never allow the plants to grow untrimmed to the final height before shearing; by that time it will be too late to get maximum branching at the base. After the hedge has reached the dimensions desired, trim closely in order to keep it within bounds.
Pruning a Formal Hedge
Start by pruning the top flat. If the hedge is not too long, you should be able to cut by eye, stepping back occasionally to check your progress. If you don’t trust your eye, hammer two stakes into the ground and stretch a length of string between them to use as a cutting guide. Next, cut the sides, making the top narrower than the base. Brush off trimmings from the top of hedge and from the base of the hedge to prevent the spread of fungal diseases.
Low growing formal hedges used for parterres, knot gardens or as borders around vegetable beds can be kept neat by trimming twice a year. Cut box hedging in spring and then in mid-summer. Use string stretched between two stakes to ensure the top is flat and then cut the sides vertically.
Pruning an Informal Hedge
Although flowering, native and informal hedges are allowed to grow naturally so that their shape isn’t spoilt, that does not mean they never have to be pruned. If neglected they could soon grow too tall or spread out of control. To keep them in good shape, occasionally remove old stems with secateurs.
Pruning deciduous hedging plants
The establishment of a deciduous hedge begins by choosing young plants 1 to 2 feet high. When planting, cut the plants back by a third of their height including the strong side shoots. This will induce low branching. Before bud-break in the next season, prune half of the new growth. In the following year, again trim off half the new growth to encourage branching.
In the third year, start shaping. Hedges are often shaped with flat tops and vertical sides. This shape is occasionally unsuccessful. The best shape, as far as the plant is concerned, is a natural form – rounded or slightly pointed top with sides slanting to a wide base. After plants have been pruned initially to induce low branching, the low branching will be maintained by trimming the top narrower than the bottom, so that sunlight can reach all of the leaves on the plant. Rounded or peaked tops also aid shedding snow, which if left, may break branches.
When to Prune
The frequency that you will need to trim your hedge will depend on the type of hedge you have and the type of finish that you require. Fast-growing species, such as privet and some conifers, Leyland and Lawson’s cypress, for example, may need trimming two or three times in the spring/summer to maintain a dense, formal effect.
Most conifers can be pruned in spring/summer. This is also suitable for slow-growing evergreens such as holly and yew. More vigorous evergreens, such as box, benefit from a trim in late spring. Deciduous species are usually pruned twice annually, first in winter while dormant and again in mid-summer.
Once your hedge is trimmed to the desired shape, water and mulch the plants to keep them in good condition. Occasionally a hedge plant can die or become damaged through disease – if it’s not possible to save the plant, wait until autumn and replace it.
DGK Lawns and Gardens can shape and cut hedges to your desired design, contact the team today to start pruning.