Hedges

How

Trimming

Cutting strategies can be tailored to suit the hedgerow species present on the farm, adjacent habitats and the local landscape character. Tall hedges with plenty of hedgerow trees are ideal for connecting woodlands, helping the movement of small mammals and amphibians through the landscape, and for foraging and navigation by bats. Hedges with wide grass or wildflower margins are ideal for connecting unimproved grasslands. Short hedges without trees are better in areas where ground-nesting birds prone to predation breed.

Hedges should not be trimmed during the peak nesting season for birds, between March and September. If you can delay trimming until January and February, the berry crop will provide valuable food for wildlife. If this is not possible, a 3-year rotation is required to provide a bumper crop of berries in one year of the rotation. Cutting is usually undertaken with a flail, but a circular saw is a less damaging alternative which creates a cleaner cut and encourages better re-growth.

Rotational trimming of hedges ensures an annual resource of flowers and berries. In a 2-year rotation, cut half of the hedge each winter (a 2-year rotation with a cut in autumn provides little benefit compared to annual trimming). On a 3-year rotation, cut a third annually. Avoid cutting the entire hedge in the same year to provide continuity of habitat and resources. Hedges can be cut rotationally across the whole hedge (both sides and top) or can involve leaving one side uncut or leaving the top uncut to encourage upward growth. A sheltered, south-facing area of hedge left uncut each year will provide an important refuge for insects.

Some hedges can be allowed to grow taller and wider by not cutting back to the previous cut line annually (reduced cutting intensity), allowing a small expansion each time. This can create a greater variety of hedge sizes around the farm. Reduced cutting intensity can be useful for an early autumn cut on hedges in wet areas where a late winter cut may not be possible.

Grass buffer strips

Buffer strips of at least 2m will protect the hedge from inputs and provide habitat for wildlife. Where a hedge includes several mature trees, extend the buffer strip to protect the roots from damage during cultivation.

Grazing livestock can reduce the wildlife value of hedgerows, and even threaten its long-term survival. If fencing is required to protect the hedge, erect it 2 to 3m away from the centre of the hedge. Rather than tightly following the curves of the hedge, consider fencing longer straight runs, so that some rough grass can develop where the fence is further from the hedge.

Restoring gappy hedges

Planting up any gaps is best undertaken using locally-sourced native hedge plants in early winter, when the ground is warm and moisture is available.

If existing hedgerows lack a thick base, combine planting with coppicing to give the new plants minimum competition. Before planting, the ground should be free of vegetation (use a suitable herbicide if necessary). Alternatively, you can plant through black polythene to suppress weeds and reduce moisture loss.

It may be necessary to use plastic tubes, spirals or quills to protect young plants from grazing rabbits or deer (removing the cuttings if possible).

Restoring overgrown and leggy hedges

If a hedgerow has lost its bushy base and resembles a line of trees, it can be restored in the winter through laying or coppicing.

Laying (cutting stems part way through and interweaving them along the hedge line) has a less drastic effect on wildlife than coppicing, but needs skilled labour. Recommence trimming in the following winter, and in the direction in which the stems have been laid.

Coppicing (cutting the stems at ground level) is best where the hedge is too overgrown to be laid because the stems are too thick. The stumps may need protection from browsing by rabbits and deer.

Both forms of management will reduce breeding opportunities for birds in the years immediately after management, so should be carried out over many years rather than managing large sections in one year. If there is any potential for bat roosts being present, these must be taken into account before work is undertaken and if necessary specialist advice sought.

If possible, pile removed wood somewhere that does not interfere with farming operations to provide valuable dead wood habitat and refuge areas for wildlife.

Hedgerow tree management

Mature and dying trees are home to a wide variety of insects and other animals that may not be found elsewhere on the farm. Because of their importance, such trees require protection and a long-term plan to replace them.  Tag native saplings in the hedge that have not been cut in previous operations and leave these during future trimming. Choose species that are present as hedgerow trees in your area, such as oak, ash, cherry or willow. Alternatively, native saplings from local sources could be planted.

Retain old, dying and dead trees where these are not a hazard, as they support important insect communities, bat roosts and may be used by hole-nesting birds. Rotten tree stumps and voids around root systems are features which may be used for hibernation by reptiles and amphibians.