Renovating an Overgrown Hedge

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Renovating an Overgrown Hedge

Numerous hedge varieties exhibit positive responses to renovation, such as beech, box, hawthorn, holly, hornbeam, Lonicera nitida, and Yew. These hedges can undergo a substantial reduction of up to 50 percent in both height and width through a single cut. However, for more drastic renovations, it is advisable to implement the changes gradually.

Overgrown hedges pose a common challenge, as they can easily take over a border and prove challenging to keep in check. Revitalising an ageing hedge through renovation is a practical solution. Given the legal regulations regarding the height of evergreen hedges, opting for renovation becomes a wise choice when these green boundaries become unmanageable.

On the contrary, most conifers, with the exception of yew, do not fare well with renovation, as they lack the ability to reshoot from old wood. Regular light trimming is essential for conifer hedges, and if they have become overgrown, a method for partial renovation is outlined below.

Hedge Renovation Quick Guide

Key Points:

Recommended for: Overgrown hedges
Best Timing: Mid-winter (for deciduous hedges); Mid-spring (for evergreen hedges)
Level of Difficulty: Easy to moderate

When to Renovate a Hedge

For deciduous hedges, the optimal time for renovation is midwinter, during their dormant and leafless phase.

On the other hand, evergreen hedges should undergo renovation in mid-spring. During this period, they are actively growing, making them more responsive to pruning, and the risk of frost has subsided, ensuring a favourable environment for the rejuvenation process.

How to Renovate a Hedge

Prior to commencing any hedge work, it’s crucial to verify that there are no nesting birds present, as per the Wildlife & Countryside Act 1981. Damaging or destroying the nest of any wild bird in use or under construction is considered an offence.

In cases where significant renovation is required, involving a reduction of more than 50 percent in height or width, it is advisable to approach this process gradually, ideally staged over a span of two or three years. This measured approach helps minimise stress on the hedge and promotes a healthier rejuvenation process.

Year 1 Renovation Plan:

Trim the width on one side of the hedge exclusively.
Cut it back to at least 15cm (6in) less than the intended width, or trim almost to the main stems if required.
Remember to employ a ‘batter’ cut, creating sloping sides that taper from the bottom to a thinner top. This design facilitates light penetration to the bottom of the hedge.
Trim the other side of the hedge using standard methods.
Maintain the existing height without alteration.
Apply mulch and feed in spring to stimulate robust re-growth.
Allow the hedge a full growing season for recovery.
Ensure ample watering, especially in dry spells during the first growing season post-renovation.

Year 2 Renovation Plan:

Trim the opposite side of the hedge, cutting almost to the main stems if needed.
Cut to a similar ‘batter’ as the previous side, maintaining the sloping sides for optimal light exposure.
Keep the height unchanged.
Apply mulch and feed in spring to promote robust re-growth.
Allow the hedge a full growing season for recovery.
Ensure thorough watering, especially during dry spells in the first growing season following the renovation. This helps support the hedge’s health and revitalisation.

Year 3 Renovation Plan:

Reduce the height of the hedge to at least 15cm (6in) below the intended height.
Execute more substantial cuts where the upper sections of the hedge appear open and patchy.
Apply mulch and feed in spring to stimulate robust re-growth.
Allow the hedge a complete growing season for recovery.
Ensure thorough watering, particularly during dry spells in the first growing season following the renovation. Adequate water support is essential for the hedge’s successful recovery and renewed vitality.

Conifer Hedge Renovation

Renovating conifer hedges differs from the approach taken with deciduous and evergreen varieties. Most conifers, excluding yew, lack the ability to re-sprout from old wood.

Examples of conifer hedges that do not respond well to hard pruning include Cupressus, Chamaecyparis, and × Cuprocyparis leylandii (Leyland cypress).

If a conifer hedge has become overly large, consider the following steps to reduce its impact without a complete renovation:

Reduce the height by up to one-third in April.
Thin out the side branches, removing selected branches back to the trunk while leaving others intact. This promotes increased light and air circulation around the hedge.
Apply mulch and feed in spring to encourage vigorous re-growth.
Allow a complete growing season for recovery.
Water well during dry spells in the first growing season following renovation.

It’s essential to note that hedges reduced in height by more than one-third may not fully fill out, potentially remaining flat and bare at the top. This highlights the importance of careful pruning to maintain the hedge’s overall health and aesthetic appeal.

Will Full Renovation Help My Overgrown Hedge?

Renovation pruning inevitably results in ugly bare patches, but re-growth should be sufficiently rapid to hide these within one or two growing seasons.

Where holes or bare patches have developed in conifer hedges intolerant of renovation, it may be possible to tie in a new branch to that bare area in order to cover it.

Brown patches can be a problem in some species of conifer hedge for one or more reasons. Environmental factors, pruning at an inappropriate time of year, aphids or fungal diseases may be to blame.

When reducing the height of a long hedge, it can be difficult to get a straight line along the top. Painting an indicator line of whitewash along the hedge just above the point of cutting may help. Alternatively, set up a string line along the hedge to act as a cutting guide.

If recovery seems poor after the first or second stage of renovation, delay the next stage for a further year to give the hedge time to re-shoot.

Hedge Looking Thin at the Base?

Where hedge growth is robust but thinning near the base, the practice of “laying” can effectively revitalise the hedge by promoting new growth. Hawthorn is particularly well-suited for laying, although many common deciduous hedge shrubs like ash, blackthorn, elm, field maple, and hazel are also suitable candidates. To gain expertise in hedge laying, courses are available through the National Hedgelaying Society.

Step-by-step guide to hedge laying:

Choose the Winter Season: Hedge laying is best performed during the winter months, typically on the ditch side of the hedge.
Allow Growth: Let the hedge reach a height of about 2.5-5m (8-16ft) with main stems measuring 5-10cm (2-4in) thick at the base.
Select Stems: Remove stems larger than approximately 20cm (8in), those with awkward shapes, or those out of line.
Clear Lower Growth: Cut away side growth from the lower stems and clear debris from the bottom of the hedge.
Prepare Pleachers: Cut almost through the main upright stems (pleachers) near the ground on the opposite side of the intended lay direction. Push them over at an angle of about 35° in the direction of the rising slope.
Install Stakes: Drive hazel or ash stakes into the hedge line every 40cm (16in) and weave the pleachers between them.
Secure with Binders: Use twisted binders or heathers made from coppiced hazel, sweet chestnut, or willow to secure the pleachers around the top of the stakes.
Trim Stubs: Trim the cut stubs of the pleachers to prevent the stools from rotting.
Fill Gaps: Any unwanted pleachers cut from the hedge can be utilised to fill gaps at the end of the laid hedge.

By following these steps, the process of laying can enhance the density and structure of the hedge, contributing to its overall health and visual appeal.