ARE THERE PROBLEMS BUYING AND PLANTING LARGE PLANTS IN THE WINTERY WEATHER WE HAVE AT PRESENT?

We sell large trees and hedges throughout the year but I have to face the fact that there are problems buying and selling in extreme weather like we have at present. There are obvious difficulties with transport butalso more subtle, long term problems with hardiness and survival of the more tender species. Last winter, which was tough for many people here in the UK, was even more extreme in parts of mainland Europe including countries where many of our plants are grown. How can we be sure that normally hardy plants which we buy and sell at this time of year will thrive. Basically I'm not sure we can and replacement of failed specimens appears to be the only answer.Last year parts of the Netherlands had more extreme weather than we had in the UK with temperatures falling much lower. One result was that some evergreens such as laurels, bought widely from Holland for hedging and screening, appeared fine when delivered in early spring but several of them dropped their leaves soon after and appeared completely dead. Customers buying these needed them replaced and we, and the nurseries who supplied them, were happy to arrange this. Of course we had to be satisfied the plant deaths were not the result of poor planting and aftercare. The landscapers who bought and planted these explained to their customers that they were bought in good faith and that it is not always possible to be sure from the appearance of plants bought after extreme weather that they are still thriving. Buying deciduous plants can also be difficult as trees and shrubs bought and planted in the winter may not show any obvious signs of death or distress until they fail to thrive in the spring.

Buying plants can be more difficult in extreme weather but what about looking after them and planting them. Advice usually depends of the kinds of plants bought. If you buy plants in containers such as pots or growing bags they are, providing they are hardy plants, able to survive for long periods out of the ground. Problems can be greater for evergreen plants as they need moisture throughout the year and protecting the roots from extended periods when their roots are frozen solid is very worthwhile. They need to be able to take up at least some moisture. Plants which are rootballed ( their roots are wrapped in hessian, or wire and hessian, which is put in the ground without unwrapping ) need to be placed away from drying winds but again these are usually capable of standing periods of extreme weather. Plants delivered barerooted need extra protection. If the ground is covered in snow or frozen so that they can't be planted on even a temporary basis, they may be better with their roots wrapped and stored out of direct wind.

Planting is never recommended when the ground is frozen or waterlogged. It's better to wait until conditions are less extreme before planting in the chosen place.

TREES ON WET LAND

If your land is often wet and cannot easily be drained there are still plenty of options for planting trees. Firstly, there are species adapted to wet ground. Willows, Alders and Poplars are amongst the commonest but a good book (such as Hillier's Manual of Trees and Shrubs - ISBN 0-7153-9942-X) will give you lists to choose from. It will also give you an idea of how high your trees may grow or other conditions, such as strong winds, which they may tolerate. Red Alder, River Birch, Liquidamber, Black Gum, Caucasian Wingnut, Scarlet Willow, Corkscrew Willow, Chinese Swamp Cypress, Dawn Redwood, Pond Cypress and Swamp Cypress will tolerate or even enjoy permanent dampness. Many other trees may survive occasional flooding but their survival chances will be improved by planting them with their rootballs above ground level. They can be planted with more than half of their rootball above the surrounding ground level and soil can then be drawn up to cover the exposed roots. Better still they can be planted into a raised mound. As the roots grow into the mound they give long term stability to the tree. In addition fewer roots will be killed by the lack of air which flooding creates and the tree is more likely to thrive. This technique allows a greater range of trees to be tried -for instance the Common Silver Birch, Hawthorn, Pin Oak , Rowan and Sitka Spruce. Native Oak (Quercus robur) and Ash will also tolerate some periods of dampness.

I HAVE BOUGHT SOME LARGE HEDGING PLANTS AND TREES ONLINE. HOW SHOULD I LOOK AFTER THEM WHEN THEY ARRIVE?

How to look after new plants which are delivered to you will depend on the type of plants and the time of year. It is essential for all plants in containers, and for all trees and hedges facing their first year in a garden, that their roots are not allowed to dry out. Judging this is not however all that easy. Large plants standing in containers prior to planting may need a lot of water during dry periods in the spring, summer or autumn. If they are from a reputable grower and the compost is of good quality they can be watered at the top of the pot until water starts to come out of the bottom. In very dry weather this may be needed every day but in general will not need to be more frequent. Once planted, watering during the first year, or even two years, will be needed in dry spells.

It is generally easy to spot stress in broad leaved plants – the leaves will start to curl and wilt. For conifers, and evergreens such as Laurels, it may not be so easy to spot these signs and by the time signs of dryness are obvious the plant may be in difficulties. For these plants it is even more vital to keep plants, both in containers and in the ground, well watered. Brown patches on conifers in particular can be difficult or impossible to reverse. Parts of a plant, or even the whole plant, may be permanently lost.

During winter months, especially once the leaves have fallen from deciduous trees, watering problems become less severe. The air is cooler and plants which have lost their leaves lose little moisture. Watering is not generally needed. There can be a problem for evergreens in the coldest months if the containers freeze solid for several days or weeks. This is because evergreen plants can still lose moisture through their leaves in the winter and this needs to be replaced by their roots. Their roots, frozen solid in pots, may be unable to provide this. In the coldest regions it may therefore be useful to find ways to prevent long-term freezing of the pots by moving them to warmer areas or insulating them with bubble wrap or straw.

Plants bought with the intention of planting them out will generally appreciate being planted as quickly after arrival as possible. Weather conditions may not allow this in the first few days. For instance the ground may be frozen solid or waterlogged by rain. Other approaches are needed. Many large hedge and tree plants provided in the winter months are rootballed. This means they have been lifted by machine and their roots have been wrapped in hessian sacking. This gives a ball of roots and soil which can be planted without removing the wrapping. The whole rootball can be planted with the top of the hessian close to ground level. If plants arrive when weather conditions prevent planting they can be left for some time. Plants in rootballs can be left away from drying or freezing winds until a suitable time arrives and, indeed, are sometimes left several weeks in the winter without suffering harm. When a suitable time for planting does arrive it is still important to ensure that planting holes or trenches do not fill with water and that the plants do not rock in the wind. On clay soils especially it is vital not to dig holes which fill with water leaving a plant's roots effectively in a pool. And in the winter, when winds are generally stronger, plants need securing so that they don't rock in the wind, loosening the roots and destroying their intimate contact with the surrounding soil. A solid stake, or a rail attached to sturdy posts, and efficient tying should achieve this.

SHOULD I REMOVE IVY FROM MY GARDEN TREES

In Britain there is always a debate about the desirability of allowing ivy to grow on trees. Many people consider that it is harmful to allow it or, at best, that it spoils their appearance.

Ivy is Britain's only native climbing evergreen and is very widespread. It can tolerate deep shade. If it were an exotic plant imported from far away it might be widely considered a great boon for gardeners. As it is, we frequently think of it as a weed. Is it actively harmful? It can of course be annoying, invading shady borders where tidy gardeners might not want it. It can radically change the appearance of a tree, removing the beauty of a clear trunk or its classic appearance. Long term experiments have shown however that the effect on the growth of a tree of allowing free rein to ivy is negligible. Only aged trees are likely to be affected by the reduction of light caused by the ivy leaves or the greater profile offered to the wind. Unlike parasitic mistletoe, ivy does not take anything from trees as it grows, it merely uses them as a means of support. In the process it provides a wonderful habitat for birds to nest, insects and invertebrates to live and bats to roost. Flowering late in the year ivy gives pollen and nectar at a time when there is little else around. These flowers produce berries in March and April which are an excellent food source for thrushes, pigeons, starlings and overwintering blackcaps.

Many people will however decide that the appearance of a cherished tree is being spoiled by ivy and will decide to remove it. This is is often easily done but keep in mind that cutting the stems of a large ivy plant on a tree will result in brown unsightly remains and these may take a year or two to fully remove. If the ivy is removed during the spring or summer it is important to realise that this may disturb nesting birds or roosting bats, both of which activities are against the law. If you still want to remove your mature ivy from a trunk it is best done in early autumn when these problems are less likely to arise.

In the end the decision to remove ivy from your trees is probably more of a personal matter. It is likely to be about neatness or the pleasure derived from seeing the uncluttered tree. In their natural situations trees and ivy, at least in Britain, have achieved a balance which provides a very valuable habitat.

HOW TO PLANT A HEDGE

Hedges come in many shapes and sizes so planting them can be just as varied. So let's start with the simplest. In the UK our landscape is crossed by tens of thousand of miles of hedges going back hundreds of years – or even longer. The majority of these were planted using very small plants, which we now call whips, and the variety of plants in the hedges has increased with time. Indeed it's possible to estimate the age of a hedge by measuring the number of different species in the hedge for every hundred metres.

The cheapest and easiest way to plant a modern hedge is to buy whips. Whips are small trees which normally have side branches, depending on the species. They are at least 2-3 years old and have been transplanted to ensure a compact and fibrous root system for successful planting. Nevertheless when you buy them they will probably look to you like sticks with a small bunch of roots on the end. They are purchased and planted in winter when the leaves are off the trees and don't look impressive at all. They are very cheap however and will soon leap into growth in the spring.

Whips can be bought to suit your local conditions. Sandy soil mixes, clay mixes and chalky soil

mixes are available and you can make up your own mixtures to suit your conditions and wishes.

You will not find evergreen plants as whips as they do not lose their leaves or become dormant in

the winter. If you want Holly or other evergreens you will have to buy them grown in small pots and they will be a little more expensive.

To plant whips you will first have to clear the ground. Small trees do not like to compete with

weeds and grasses for the nutrients and moisture in the ground. You can get round this clearing to some extent with a mulch made of a modern landscape material which will suppress the weeds and keep the roots of these small plants moister in their first, critical growing season. If you have cleared the weeds then a mulch of bark or other natural material may fulfil this function just as well. The whips are usually planted at 5 plants per metre in two staggered rows about 30cm apart. Usually there is no need to feed these tough native species but it is vital to ensure that they don't succumb to drought in their first couple of growing seasons. A mulch will help but some watering may be needed.

New plants often need protection from deer and rabbits so cheap tubes and coils of plastic are

readily available to act as guards until the plants are large enough to look after themselves.

Hedges can be planted in several other forms which give more maturity from the start. These vary from larger individual plants in pots, through plants in troughs which are starting to grow together, to fully mature hedges knitted together and planted by professionals to give a truly instant effect. Within this great range there are all sorts of possibilities. You can buy large plants up to the size of small trees which will grow into each other to form a tall hedge or screen. These are available as trimmed plants or even as squared off units which will fit next to each other to give a continuous hedge almost from day one. These are especially effective when they are evergreens (though please note that, within the UK, neighbours and local authorities can object to evergreen hedges over 2m high and require you to cut them back). When you are dealing with these plants at large sizes be aware that they may be very heavy and difficult to handle, move and plant. Professional help and even machinery may be needed.

To prepare the ground for larger plants, or troughs with several plants in them, will be more

complicated than for whips. Whips can often be planted simply by making a slit in the soil with a

spade, placing the roots of the plant in the ground and firming them in with the heel. Larger plants and especially those in troughs or with enormous rootballs, need trenches or large holes. This can cause problems in heavy clay soils where a hole dug in the clay can become waterlogged and act effectively as a small pond. This would give very bad conditions for root growth so drainage at the bottom of the hole is essential before planting.

Rootballed plants come with their roots wrapped in hessian ready to be placed straight in the ground without unwrapping. These and plants in containers need firm ground around the roots to stop them swaying in the wind – a process which stops the roots from growing into close contact with the surrounding soil. In windy situations, and especially for large plants and evergreens, it may be necessary to restrict the movement of the plants by tying them to wires attached to tensioning bolts and braced fenceposts. This however is usually a job for professionals, not for someone attempting the job for the first time.

Feeding plants with slow release fertiliser is worthwhile but the number one essential is to avoid the roots of your new hedge drying out completely during the first year or two. An automatic watering system is the best way of ensuring this but, at any rate, vigilance and an effective back-up system for watering are vital.

HOW CAN I CREATE A RAISED TREE SCREEN?

There are many situations where a raised screen of trees is useful. For instance, if you have an attractive wall which is, say, 6ft high and you wish to screen out a distant view above it without obscuring the wall you might like to use trees which have been grown as standards or high panels. What however do these different terms mean and how can these plants be used.

Standard trees are grown with a bare trunk around 6ft high (occasionally they are slightly higher at 2m and half standards are also available with shorter trunks). These bare trunks are usually easy to keep bare and you can allow the tops of the trees to grow to suit your needs. However you will need to buy trees to suit the situation. For instance a row of Birch trees may eventually grow to 45ft in good growing conditions and be 20ft across the crown but this could take many years. You would have to decide when you plant them just how far apart they should be. They will also be deciduous so the leaves will fall in winter and they will not form the same screen. There are alternatives however which will make it easier to provide a quicker and more controllable screen.

Both deciduous and evergreen standard trees, such as Holm Oaks (Quercus ilex), Laurels or the shorter Photinias, can be bought as standards and tightly clipped to create a screen limited to the size you want. Left to themselves Holm Oaks would grow as large as any Oak tree but clipped they can be kept to the size which suits you. This however requires a clip at least once a year. There are nurseries which sell a range of deciduous and evergreen trees clipped as high panels, that is bare trunks with a rectangular panel of branches carefully trained to shape on top of them. These can be planted next to each other to give an instant high screen. More decorative, but less effective as screens, are pleached trees where the high panel is trained along horizontal wires. Similarly espaliered fruit trees can be bought ready trained to give horizontal tiers of fruiting branches but these are usually on much shorter trunks for ease of picking and are less effective as screens. They are however a very effective way of dividing a garden into sections being both productive and extremely attractive.

To achieve the sort of high screens you want you will have to work out the overall width of the screen and the height which it needs to achieve. Then there is the qustion of tree variety. Do you want evergreen or will deciduous do (deciduous is often cheaper) and do you require anything else from the tree such as attractive foliage or flowers. Finally will the trees thrive in your garden conditions or will soil and drainage problems compromise their development. You will probably need to refer to a textbook or speak to an expert to answer these questions. A site visit may also be needed.