Indoor Plant Care
Information for homeowners,
garden centre personnel,
and plantscape technicians.
Pruning Trees Shrubs Roses
Since man began to keep livestock hedges have been used to enclose land. At first they were probably strips of forest left when land was cleared, the Romans planted shrubs to mark boundaries, then during the Enclosure Acts passed between 1709 and 1869 as land was taken into private ownership hedges divided up the countryside. As well as forming the boundary, hedges are sometimes used within the garden to divide up areas to give structure or obscure more utilitarian parts. They are easier to fit around irregular shapes than rigid fences and filter winds which bounce over solid structures causing turbulence.
Cutting a hedge is multi-pruning to a uniform shape. The ideal profile of a formal hedge is to have a slightly outward slope or batter towards the bottom which allows more light to reach the lower branches - usually referred to as an A-shape. A hedge of this shape is also able to better withstand strong winds and a heavy snow-fall is shed more easily. As a new hedge grows it should be lightly trimmed to promote plenty of side-shoots and form a dense structure. To obtain a straight top, a string can be stretched along at the correct height - this is very useful on a slope or undulating ground where it can be difficult to judge. The recommended method of obtaining a uniform slope to the batter to the sides is by using a lath with a cross-piece which rests horizontally on top of the hedge - like a large angle gauge.
It is easier to achieve a level finish using an electric or petrol driven hedgecutter. The 'teeth' of the cutting bar should be angled slightly downwards so that it removes enough of the growth, otherwise the hedge has a tendency to expand each year.
When using an electrical hedgetrimmer the cable should be draped over the shoulder to keep it safer. There is a new type with a rotating blade and a clipping collector, but it can only cope with fine shoots and has to be used quite frequently. With advances in battery technology cordless hedgetrimmers are now capable of working for long enough to cope with smaller hedges and topiary.
Before commencing any hedge cutting check for nesting birds - it is an offense to disturb them. It is less likely working later in the summer when all breeding should be over, however, at this time there is a greater likelihood of encountering a wasp's nest, usually there will be a few flying near the entrance, they may even have created a hole for a clear flight-path. Some species make their nest in the debris at the base of the hedge.
Small-leaved plants make the neatest formal hedges and produce the best finish with frequent close cutting. Large-leaved species such as Prunus laurocerasus (Cherry Laurel) should be pruned to shape with secateurs for the best result otherwise the severed leaves develop a brown edge or die back completely. Griselinia litoralis (New Zealand Privet) may also be treated this way, but this could be a bit tedious for a long run of hedge.
Hedges can also be informal where they are made up of various species of shrubs which are pruned to a natural shape at different heights. Also by following the methods for pruning shrubs, flowering species can be used to full effect. To have a flowering formal hedge such as Escallonia it has to be allowed to produce quite long shoots which may look untidy - they are removed immediately after flowering to allow new shoots to develop for the following year.
The time of cutting is important for most hedgeing plants. Cutting an evergreen too late can result in fresh growth emerging which will not have hardened enough to withstand cold winter winds resulting in scorching and on worse cases, severe dieback. Cutting too early will mean having to repeat the process later as not all of this year's growth will have emerged; this is particularly annoying with a long run of hedge and if employing someone to do the work. A good time for privet is late July or early August, although by this time it may look rather untidy. Nesting birds are another important consideration so by mid to late summer they should have finished, but a quick check for occupied nests is always advisable. This may also reveal the nasty surprise of a wasp's nest which can be dealt with or worked around - look out for a few wasps flying around and observe for a while to see if they are emerging from or returning to a particular spot.
The most controversial hedgeing plant is XCupressocyparis leylandii (Leyland Cypress) and its golden forms which are fast-growing and can become very dominant. They can be kept to a reasonable height and form a dense hedge, but must be cut at least twice a year to remain tidy. It is important to stop the upward and outward growth when it has reached a height which can easily be reached for this regular cutting as they cannot be reduced beyond the green growth - they do not resprout from bare stems. The tops should be stopped about 30cm below the final height, then allowed to fill out the uneven spaces. It is possible to have a normal-sized hedge of these plants, but there is a gradual outward and upward spread. There is now legislation in the UK which allows neighbours to request high hedges to be reduced, firstly by asking the owner and if unsuccessful the local authority can be asked to enforce the request if they judge it to be reasonable.
Where a hedge has become too large, most species can be cut back very hard and they will produce new growth. To reduce the height cut down to about 30cm below the final height - this will work for Conifer hedges provided there is plenty of green growth remaining below this level. It is not possible to reduce the width of a Conifer hedge beyond the green growth, apart from Yew (Taxus baccata), which will regenerate from a stump. For most other hedgeing, reducing the width is carried out over a two year period, one side is cut back close to the underlying upright branches the first year. The following year when the first side has produced lots of new shoots, the process is repeated on the other side.
Always check around the base of the hedge for seedlings of Brambles, Ivy and tree species such as Ash, Sycamore and Elder which will take over the hedgeing plants, making it very untidy and may kill parts of it off, leaving gaps in an evergreen hedge during winter when they drop their leaves. If this has occurred prune out the weed species gradually, allowing the hedgeing plants to fill the spaces - it may take a few years to achieve if the interloper has been allowed to thrive.
Something which will make cutting the hedge easier is not planting too close to it. If possible a 50cm space at the back of a border should allow enough room, although plants tend to encroach as they mature. A length of woven weed fabric laid at the base of the hedge is very useful to gather the clippings and keep them out of plants, a few spring clips will hold it in place if it is windy or tends to slip off the taller plants.
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