IS IT POSSIBLE TO RESTORE AN OLD OVERGROWN HEDGE?

A well maintained hedge can last for centuries. Indeed old boundary hedges in Britain may be over a thousand years old. But modern garden hedges are often created from a range of exotic plants and may not look good when they get old. They become too thick, gappy, full of weeds or diseased and you may be faced with the options of removing them or trying to restore them to a more useful and attractive state. So just what kind of restoration is possible.

For most conifers the possibilites are limited. When old they are usually green on the outside but the inside of them is brown, old wood. With the exception of Yew these old conifers will not re-grow if you cut back into the brown branches. They will remain brown and an eyesore. Yew however is capable of growing from brown, unpromising wood although decent regrowth may take a year or two. To restore such a Yew Hedge it is recommended to undertake the job over a couple of years cutting back one side at a time. The best time to undertake this is in spring when evergreens tend to be less active. Start near the base on one side of the hedge and move upwards cutting inside the desired final shape to allow the hedge to grow to its final shape. After this pruning the hedge should be given a dressing of general fertiliser and a mulch of organic matter to help it to recover from the works. There is no point in attempting this with a Leyland Cypress or other conifer as new shoots will not grow from the old brown wood that severe cutting will expose.

There are many other evergreen hedges which can take quite severe pruning. For instance Escallonia, Holly, Laurel and Privet can recover from fairly severe pruning in mid to late spring. They will also benefit from a feed and mulch to encourage regrowth. When reshaping remember it is normal to create hedges, especially evergreens, which are a little wider at the top than the bottom. This allows extra light to the base of the hedge which is usually more often in shadow.

Deciduous hedging plants such as the traditional Hawthorn, Beech or Blackthorn can take very severe reduction. Indeed the classic way of keeping farm boundaries as effective barriers to cattle and sheep is to lay them during the winter. This involves cutting deep into the main shoots of the plants near their bases and bending them over. They will regrow as a denser hedge than before they were cut. This is rarely appropriate for garden hedges however where a visual and practical barrier is normally needed throughout the year. It is worth noting that these plants will take any amount of reduction even down to ground level if needed. The general principle is to reduce the height and width of the old hedge to a foot or two inside the desired final height and width. The regrowth can then be trimmed each year to the shape needed

Hedges thrive on annual or more frequent clipping. This keeps the individual shoots and branches dividing from their bases instead of their ends. The result is a denser hedge restricted to the shape you want. If you leave the hedge for a year or two between cuts it will soon become a row of individual plants instead of a dense, well knitted hedge. 

WHICH IS THE BEST WAY AND THE BEST TIME TO CUT MY HEDGE?TO

There are two main reasons to keep a hedge trimmed – to make it look attractive and to make sure it grows dense. If you plant hedging plants and then leave them to grow without regular clipping you are likely to get a very leggy hedge with light between the individual plants. Left long enough, like a farm hedge that has not been cut for years, it will eventually stop being a hedge and become a row of taller trees and smaller shrubs. As such it is not likely to act as an effective physical or visual barrier.

There are several methods of trimming hedges depending on the plant varieties used. For newly planted hedges some species such as blackthorn, hawthorn and privet can be reduced to around 10cm immediately after planting. This helps to ensure that they will branch from low down and make thick hedges. Most other deciduous plants are best reduced by around a third in the autumn after planting. To keep a hedge growing densely the main leaders of deciduous plants can be cut back in the following years and side shoots shortened a little. The principle is to make the shoots on the plants divide frequently to give dense growth and this is best done by frequent trimming. In general the more frequent the trimming the denser and more formal the hedge. Once a hedge has reached the size you want the trick is to cut new shoots just outside the basic framework of the hedge allowing a small amount of new growth to be retained.

Conifers are not normally pruned until they have reached the height of the desired hedge. They can then be trimmed several times each growing season if you have the time and patience. Along with privet and lonicera nitida (shrubby honeysuckle) leyland cypress develop their best form if clipped in late spring, midsummer and autumn. Some other evergreeens such as box, lawson cypress, holly and yew do best with a midsummer and autumn cut whereas Cherry Laurel, Oleaster and Lavender should be pruned once in the autumn.

There are other details to keep in mind. If you want the leaves on your beech or hornbeam hedge to stay on though the winter, which many people do to maintain the visual barrier, they should be pruned in late summer. Hedges of laurel, holly or other broad leaved evergreen plants should ideally be cut with secateurs. If they are cut with shears you will produce unattractive brown edges on the cut leaves. Tall formal hedges should also be cut to be a little wider at the bottom than the top. This stops the bottom becoming brown, adds to the stability of the hedge (some tall hedges such as lonicera nitida have a habit of starting to lean when they are more than about 1.5m high) and reduces the likelihood of snow pulling the hedge apart.

There are many other details to maintaining a good hedge. I would recommend the RHS booklet called simply “Hedges” by Michael Pollock ( ISBN 0 7513 47280) as a very good introduction to the subject.

HOW CAN I GROW AN EVERGREEN HEDGE RIGHT NEXT TO THE SEA

Growing by the sea can have both advantages and disadvantages. Plants sensitive to cold conditions may be helped by a milder climate than that found inland where the moderating effect of the sea has no influence. On the other hand salt laden winds are a problem for very many plants and only a minority are well adapted to them.

Griselinia is a classic, and frequently very effective, evergreen hedging plant for coastal areas. It will form dense attractive hedges in areas which are never exposed to very cold winds. There are other evergreen hedges which might be suitable in areas which aren't exposed to very cold winds - varieties of Escallonia, Holly, Bay, Choisya, Cotoneaster, Euonymus, Hebe, Pittosporum, Pyracantha, Viburnum, and Leyland Cypress. In addition Holm Oak, Junipers and especially Pinus nigra might stand up to very cold winds. Much depends on whether you want a low, formal hedge or a larger, less restricted visual barrier, such as Pinus nigra would give. Holm Oak and Leyland Cypress might also provide this.

WHY HAS MY LEYLAND HEDGE DEVELOPED LARGE BROWN PATCHES AND WHAT CAN I DO ABOUT THEM?

Problems with brown patches on Leyland Cypress hedges seem to be increasingly frequent. Hedges which had grown happily for many years develop brown areas which can vary from a few inches across to several feet. Hedge owners are then faced with a dilemma. Can the hedge be saved or improved or must it be removed entirely.

The Royal Horticultural Society (http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=132#top ) suggests that there are two major reasons why these patches might appear – attack by aphids and fungal diseases. Damage caused by aphids develops in late spring and summer and is found more often at the base of hedges though it can develop at any height. The browning can develop long after the aphids have left the foliage. The RHS suggest that spraying can be effective if the aphid attack is caught early and that some regrowth of new green shoots is possible. As a general rule however growth of new green shoots on brown conifers stems is slow if it happens at all.

Fungal disease is also a common cause of brown patches. Over enthusiastic hedge trimming, especially at times when a hedge is stressed, may increase the likelihood of die-back. They suggest that trimming in April, June and August is safer than in autumn. They especially suggest that you don't trim in hot or dry periods or in the autumn and that you never cut into old wood but only trim the outside growth. By old wood they mean thicker stems deeper into the body of the hedge. Feeding and mulching of the hedge in late winter, in preparation for spring growth, is recommended.

With an established hedge there may be nothing significant to be done to remove the brown patches and it could be necessary to take the plants out entirely. To replace the removed plants can be a difficult matter as the roots of an old hedge will be extensive and they will have removed most of the nutrients from the ground for quite an area around. Full removal of the stumps and replacement of the surrounding soil is the most likely way to provide a decent environment for a new hedge to grow. This might need the use of a mini-digger and is likely to involve professional landscapers. As replacements you should consider tough evergreen hedges such as Laurels, Portuguese Laurels or Western Red Cedar which would grow relatively quickly. Ivy screens are an option where an instant evergreen fencing/hedging solution is needed which will stay at around 2m high. Yews may also thrive and provide excellent formal hedges long into the future. All are less likely to suffer from the problems which Leyland Cypresses are prone to.

Garden Trees and UK Law

We sometimes receive enquiries about the legal situation regarding trees in domestic gardens and try to give some basic guidance. The information given below is offered in good faith to cover some situations in the UK but we can't guarantee that it will apply in all situations. Before taking any of these matters further please check with your local authority or a bona fide legal adviser.

1. Q A neighbour's tree overhangs my garden, cuts off the light to my house and blocks my path. What can I do about it?

A The first thing to know is whether the tree is covered by a Tree Preservation Order or is in a Conservation Area.. Permission from the Council may be needed in either case to undertake work on the tree so start by contacting the Tree Officer from your local authority. In civil law you can take back to the boundary line any branches that overhang your property from trees not covered by these restrictions. This can be done without informing your neighbour or gaining their permission but it is always better to let them know in advance. In law the timber removed belongs to the owner of the tree and should be offered to them. If you think that a tree blocks off light to your house or garden without overhanging your property then the problem becomes more complicated and you may have to take legal advice after you have spoken to the owner of the tree.

Similar points apply to overhanging fruits which technically belong to the owner of the tree. However you have no right to insist that your neighbours clear up fallen leaves or fruit in your garden.

2 Q Do I need permission to cut down or prune a tree in my garden?

A Again you need to check whether the tree is covered by a Tree Preservation Order or is in a Conservation Area. Contact the Council Tree Officer to clarify this. You will also need permission from the landlord if you are in rented property. If you are in a newly built property trees in your garden may be covered by the original planning permission for up to five years so there may be restrictions as to what you can do.

3 Q My neighbour has a high evergreen hedge which is cutting out my light. Can I make him cut it down?

A The first thing to do of course is to discuss the options with the owner of the hedge. If this fails to produce the result you want then the local authority is empowered to adjudicate. You will need to approach them formally and to pay them a fee. They may dismiss the complaint or issue a formal notice of remediation to the hedge owner to remedy the situation. Usually this means a reduction of the height of the hedge to no less than 2 metres (about 6ft 6in). If the hedge owner doesn't carry out the work the Council can prosecute, issue a fine, and undertake the works themselves and recover costs. Information on this process is available from

http://www.communities.gov.uk/publications/planningandbuilding/overgardenhedge

http://www.communities.gov.uk/publications/planningandbuilding/highhedgescomplaining

4 Q How can I get a Tree Preservation Order made

A This is a legal process which is decided and implemented by your local authority Tree Officers.

5 Q My neighbour has started to cut down a tree. Is he allowed to do this?

A If the tree is not protected (see question 2 above) then he won't need permission unless -

a) the tree is on a joint boundary or access is needed to the adjoining property to undertake the works. Permission under civil law is then needed from the other party or

b) the tree is so large that the work, especially felling, poses dangers to land and property and would therefore require clearance under Health and Safety regulations.

6 Q What can I do if I see someone working on protected trees and I think that they may not have permission?

A Firstly don't take the law into your own hands but approach the owner or tradesperson

politely and ask them whether they know whether the tree is protected and whether they have approached the local authority for permission to work on it. If the situation remains amicable ask whether you can see the written answer from the Council officer. If you don't feel able to do this you can approach the Council tree officers directly to inform them about the situation. If it is out of work hours you should report the matter to the Council as soon as possible on a working day making as many notes of the details as possible. This might help if the Council decides to start a prosecution. You can also approach the police and ask to speak to the wildlife officer if you think that there may be danger to protected species or it is the bird nesting season.

I

Should I Be Watering My Trees After This Dry Spring

This has been an exceptionally dry spring in most of the UK. Only the north west has received normal amounts of rain. It has followed a very cold winter and a recent prolonged windy period has itself caused extra drying. There are worries that the combination of extreme seasons may be of particular harm to larger plants which have been planted within the last couple of years. These may not yet have developed the extensive root systems which would see them through a drought and the result could be die-back or the death of the plants. A sign of the stress which the plant is suffering might be the loss of leaves or sections of the plant or, for fruiting trees, the loss of fruit. Remember that the rain showers of the recent weeks may not yet have penetrated far enough into the ground to reach lower roots.

If you are worried that these conditions might apply to your plants, or you see signs of stress, then now is the time to take action. Fruit trees in particular may need attention as fruit, which is mostly water anyway, will be swelling and may require more water than the tree can provide. Fruit trees may cast off a large percentage of their growing fruit to reduce the stress they are suffering. To counter this a regular application of a trickling hose to the soil surface around the trees will help. If this is not possible then a bucket, or watering can, of water applied regularly may have the same effect. Action now may prevent fruit fall, leaf loss or the death of a large plant.

Planting trees near to houses and walls

The question of how close to your house to plant a tree is a complicated one. After a dry summer there is usually a rush of claims to insurance companies after subsidence occurs. The problems generally happen in areas where there is clay soil as tree roots can remove the water from the clay producing shrinkage. This shrinkage may result in movement of foundations and the walls which they support. Exact information is hard to give but it is possible to give a few generalisations. I take my information from a textbook on the subject - "Tree Roots and Buildings" by Cutler and Richardson published by Longman Scientific and Technical. They work from reported problems and give the distance from buildings within which 50% of the incidents occur. If the incidents occur close to a building for a particular species this is considered to be a less dangerous tree to plant than one which gives problems at a greater distance from the house. So Willows, Poplars, Oaks and Elms can give problems at far greater distances than Birches, Hollies, Apples Rowans, Pines, Yews, Magnolias, Laburnums, and Cherries.

It may be wise to consult your insurance company before you plant a large tree in your garden. Be aware however that they are likely to give a very conservatve reponse and that our towns and cities would have far fewer fine trees in them if insurance companies had been the arbiters of what to plant.

There is another way to look at this problem. In many countries street trees are planted into prepared planting pits along the sides of roads. These are effectively large sunken plantpots which allow space for tree roots to develop without interfering with buildings, drains or other services. If you are keen to plant a large tree into a space near to walls, buildings, or services it may be possible to create a pit. For large trees you would need a pit around 2m x 2m and 1m deep. This would have thick walls of blockwork or alternatively welded steel. You would be making an enormous container with drainage holes to prevent it turning into a sump or underground pool. It would be essential to ensure that the container can drain properly and so it is unlikely to work if the pit is dug into clay unless you can arrange good drainage through the clay and away.

In order to water the tree effectively and, almost as important, to allow air to the roots a perforated plastic tube around 50mm in diameter should be buried to the depth of the pit but with its inlet just above soil level. These are available from tree and landscape suppliers but you could improvise one from a length of drainage pipe.

If made well this should allow a tree to thrive in a limited space without danger to its surroundings.