Before choosing a hedge there are a number of practicalities to be considered, particularly in the light of new legislation e.g.
Exposure! Will the chosen variety tolerate high winds or sea spray in coastal areas?
Probably the best way to answer these questions is to study hedges in your locality and see what grows best.
The appearance of a hedge generally depends on its maintenance and general aftercare.
This will probably entail at least one trim each season to keep it looking its best, particularly with fast growing subjects such as; Honeysuckle, Lonicera nitida and Privet.
Leylandii conifers make excellent hedging providing they are regularly trimmed, if left unchecked they can grow impossibly tall, which could lead to problems with your neighbours.
Dig along the line of the new hedge to at least a spade depth i.e. approx. 300mm (12”) deep and 600-900mm (2’-3’) wide, and incorporate copious amounts of organic matter.
If the area has a tendency to get very wet, improve the soil by adding horticultural grit.
If water-logging is a problem, lay a suitable land drain.
Conversely, in dry areas, consider installing a trickle irrigation system.
Autumn to early winter (Week 40>)is the ideal time to plant out a hedge.
Most hedging plants are supplied bare-rooted, although some might come as container plants.
These are best planted while they are dormant, but avoid planting out in cold wet weather, or when ground is frozen.
If you are unable to plant immediately after delivery, ensure the roots are kept moist and free of frost.
For longer-term storage, heel them in at the same level at which they were grown in the nursery, with a view to transplanting them when conditions improve.
When planting, trim back any damaged roots to healthy growth.
Ensure the planting hole is of sufficient width to allow the roots to be fully spread out.
The planting depth should be as it was on the nursery, this can be seen by the soil mark on the stem.
Planting distances can vary and are generally dependant upon the cultivar being planted, and the eventual thickness of the hedge.
Plant single row hedges approx. 300-600mm (24”-36”) apart.
For thicker hedges, plant a staggered double row at the same centres as above, with 500-600mm (18”-24”) between rows.
Work soil between the roots with your hands, firm plants in with your feet, then water and mulch.
It does not follow that larger specimens are best, smaller plants tend to establish better and their rate of growth usually outperforms larger specimens.
Ensure plants are well-watered for the first two growing seasons.
Top-dress annually with a general purpose fertilizer.
Keep the area weed free, and re-apply mulch as required.
In exposed areas, erect a windbreak on the windward side, until plants are established.
If rabbits and deer are a problem, protect the young plants with tree guards.
Pruning / Trimming:
You may have to clip conifer hedges three times during the summer, with the first cut in May and the last in late summer.
When pruning / trimming clip the hedge to the desired shape and height.
With new hedges stop (cut off) the leading shoots at the desired height.
Box and yew can be clipped in May to keep the edges sharp and then given a second trim in late August or early September.
Commence trimming conifers when they are quite small, and certainly long before they reach the height and width you require.
Doing so should result in producing even healthy growth.
Allowing a hedge to get out of control can result in brown bare patches being formed when the hedge is eventually cut back to the desired height and thickness.
Trimming a formal hedge:
Stretch a string between two temporary posts to form a guide line to the height / level / gradient you require.
Then beginning at one end, start cutting from the base and work your way up to the final height.
Continue this method in sections about one metre wide until you reach the end of the hedge.
When trimming the sides slope them back towards the top of the hedge so that the hedge is slightly wider at the bottom than the top.
Apart from giving a softer appearance, this also helps to avoid shading smaller plants planted at the base of the hedge.
Finally cut the top of the hedge to the desired heights / levels, removing the posts and string on completion.
Should you want to form topiary shapes prepare ply wood or wire templates in advance and cut your hedge to suit the template shape/s.
Leyland cypress hedges:
Despite much bad press, leylandii hedges make excellent and quick-growing hedges.
The bad press has generally been brought about by people neglecting the hedge and allowing it to get out of control.
Had they been regularly trimmed this problem would most likely not have occurred.
Leyland cypress need regular pruning, clipping may be required three times a year from April onwards.
To keep the hedge evergreen aim to keep the hedge wedge shape or ‘A’ shaped i.e. flat narrow top with a wide base.
If the shape is the converse of this it is likely to become bare at the base.
Renovating overgrown Leyland cypress hedges is difficult, i.e. they cannot be greatly reduced in size when too large.
New growth will not sprout from old wood below the outer green foliage, which means all pruning must be done to the younger shoots.
Hedges may respond to shortening in stages, e.g. remove up to one-third off the height, in April.
Removing too much can result in a bare, flat-topped hedge, or even death of individual plants.