Trimming unlaid hedges
You can apply the normal rules for pruning to hedge shrubs with a view to encouraging dense growth from top to bottom of the hedge. If the intention is to allow the hedge to grow up for laying then typically you would trim the side of the hedge whilst allowing the top to grow up with minimal trimming.
Trimming laid hedges
- The overall objective is to make the hedge as thick as possible and to maximise the intervals between laying, which is a time consuming and relatively expensive activity. There is a trade off between getting the hedge tall again as quickly as possible and thickening it up as I am forever telling customers when I am laying hedges!
- Whether trimming mechanically or by hand, the direction of trimming should follow that of the laying so that you are trimming with rather than against the lay of the hedge. This minimises the damage to stems as they are cut. If trimming mechanically, the equipment used must be able to cut the regrowth cleanly and with minimum damage to the stems. Torn as distinct from cleanly cut stems are not only unsightly but promote disease and dieback in the stems.
This laid hedge has been well trimmed mechanically by flail and is consistently thick and even
The next 10 images show a mixed garden hedge in Tring in October 2016 before and after an annual trim done by the householder using a hedgetrimmer.
By co-incidence I was laying a hedge for his neighbour at the time. I was impressed how neat a finish he achieved.
I originally laid this hedge in 2014 (to see how it looked then, see here )
During spring and summer a headland is left.
This makes cutting the grass easier and allows the hedge to bush out a bit.
A vertical cut to the side and a horizontal cut to the top reveals the laid stems as well as the newer vertical growth. A reasonably amount of leaf has been left, though it won't be long before the leaves will shed anyway.
The way to leave a more leafy finish would be to leave the hedge wider at the bottom than the top by tapering the side of the hedge.
Since trimming has taken place horizontally at the top and vertically at the sides a lot of the new growth has only been cut at the top. The hedge could be made more bushy by cutting at different heights with tapered cutting as mentioned above. Possible drawbacks to this are firstly that it would take longer and be more difficult to achieve a uniform finish and secondly that the hedge would take up more room.
It is more difficult to get a uniform finish to a mixed hedge as the different plants growing differently.
Looking along the side of the hedge it has a very pleasing finish overall.
The top of the hedge is perfectly even and gives a fine view of the field beyond.
To the right of this image you can see the binding from when the hedge was laid, so the overall height is little different from when I laid it.
A mixed species hedge gives more interest than a single species hedge and is better for wildlife, but makes it more difficult to attain a regular finish.
- The first time a laid hedge is trimmed it should be cut just above the top of the stakes. Where possible, the sides should be trimmed at an angle, the wider the hedge, the shallower the angle.
Wider hedges, which are the most beneficial for wildlife, are easier to achieve where you have plant species which will sucker such as blackthorn and where there is no ditch to keep clear. Ideally, the new growth at the outer edges of the hedge should be cut as low to the ground as practical. As well as getting the hedge to bush out from as low as possible, this will also thicken the hedge up at all levels. If you just "top" the hedge, you will end up with a lot of undivided stems 4ft or so tall, which is not what you want.
This ash and plum hedge has been trimmed by hand two years after laying. By stepping the cuts as shown the hedge will bush out at all levels as it starts to regrow.
- Where the requirement is for the normal informally managed country hedge rather than a formal and annually trimmed town hedge, trimming need not take place more often than every two to four years. As well as saving time and money, this also benefits wildlife since you only get blossom and fruit from previous years' growth.
- Successive cutting of the hedge should be further out and up each time to further promote thickening of the hedge. Repeated cutting at the same level is bad practice and causes progressive damage to the hedge.
A tall well managed hedge is likely to have several horizontal lines visible in winter where it has been cut mechanically in the past. Once a hedge reaches the maximum height required, then providing, there is no requirement to lay it to fill in any gaps, it is quite acceptable to significantly reduce the height of the hedge once more. This will involve cutting through relatively thick wood and is likely to require the use of a saw attachment rather than a flail. The hedge can then be allowed to grow up again and managed as before.
It is generally reckoned that the best time to trim a hedge is late winter when there are no berries or fruit left in the hedge for the birds and when there is not a hard frost.