Advice
RHS Help & Advice
Hedge renovation
Type
and time
Many hedges respond well to renovation, such as beech, hawthorn, holly, hornbeam, Taxus and Thuja pilcata, and these can all be reduced by as much as 50 percent in both height and width in a single cut.
Most conifer hedges cannot be hard pruned as they do not re-shoot from old wood, so require regular light trimming (an exception to the rule is yew, which can be cut back hard). Renovate deciduous hedges in mid-winter, evergreens in mid-spring. If possible, feed the hedge well in the season prior to renovation.
Rejuvenation pruning
Prune deciduous hedges in midwinter and evergreens in mid-spring. Because hard pruning removes many growth buds it is best carried out in stages. If reducing both the width of the hedge, cut back the top and one side in the first year, and cut the other side the following year (see illustration, right). If recovery is poor delay the second cut for another 12 months.
To reduce the height of a hedge, cut hard back to 15-20cm (6-8in) below the final desired height.
To ensure the hedge is cut back to the right height and width, use garden twine stretched between stakes at the right height and width as a template to work with. Ensure the hedge tapers towards the top so plenty of light can reach the base.
Conifer hedge renovation is limited to tying-in branches to cover holes.Stretch twine between stakes at the right height and width as a template to work to.
Maintaining a good shape
Use garden lines tightly stretched between stakes as a template. Ensure the hedge tapers slightly towards the top, so that optimum light reaches the lower parts of the hedge.
Aftercare
It is essential to mulch and feed hedges after renovation. Spread a nutrient-rich mulch, such as garden compost or well-rotted manure around the hedge after pruning. Alternatively apply a general fertiliser such as Growmore over the root zone at the first signs of new growth. Water the hedge thoroughly during dry spells in the first growing season following renovation.
Further
information
The illustrations above have been taken from the RHS Practical Guide to Hedges, published in spring 2001 by Dorling Kindersley.
Hedges and nesting birds
When undertaking work on garden hedges check that there are no birds nesting as it is an offence under the Wildlife & Countryside Act 1981 to damage or destroy the nest of any wild bird while it is in use or being built.