Incompetent pruning can lead to a form of horticultural vandalism

Press, 22 February 1980, Page 8

Incompetent pruning can lead to a form of horticultural vandalism

The silver birch and the flowering cherry are two trees which, seem to get more than their fair share of mistreatment through unskilled or poorly informed use of the saw. Maybe it is because the subjects were unsuited for the position in the first place, or because their ultimate dimensions were not initially realised, but

the most common form of mutilation of these trees is to bring them down in height and “square them’’ off.

Unfortunately', neither the birch nor the cherry is particularly tolerant to straight out cutting back, especially if it is not done properly, and more so if it is repeated. Most ■ silver birches available from the nursery possess good shape and do not often need any initial pruning with the exception of perhaps a few branches which may be emananting' from a little too low down on the trunk. .

The ultimate height is in the region of 20m and it does not usually form a very spreading tree. Unless misshapen to start with, influenced by sur-

rounding trees or prevailing weather, it could well be said that the birch will develop and maintain a good to exceptionally good shape with minimal assistance. It makes a fine specimen shade tree of deciduous habit and graceful appearance. The small leaves have a fresh colour when young and turn an attractive orange yellow in autumn before they drop. The silver birch also looks good in groups or clumps, and lining avenues and driveways. It does not take kindly' to rough cutting back and any stubs which are left are inclined to rot. The shedding of seed from established trees seems endless at the time and can be very messy; similarly leaf fall will see a thick carpet of them on the ground but they make good compost. The silver birch is host to aphid and the sticky' honevdew exuded by these insects can be upsetting when it drips on clothing or vehicles below. Drv summers may see the leaves colour and fall prematurely. Flowering cherries always attract attention when in flower; many of them also possess the virtue of autumn as well as spring foliage colour and some provide a bonus of verv edible fruit as well. There is often an urgent need to do some initial pruning for shape when the young tree is first planted, but once a balanced framework has been achieved, heavy surgery should be minimal. As with the silver birch, the cherries are not trees to mess about with and any hard cutting back that is done in later yars should only be attempted if you are fully aware of what and how the job is to be done. This is partly because it becomes a simple matter to destroy shape and upset the growth pattern but also because the cherry tree is very susceptible to silver leaf, an infection for which there is currently no cure. It should be noted that while it is said that cherry trees should not be cut back they will need attention as they get older. There will be a need for timely removal of crossing and unwanted growths and also dead wood. As the tree ages so do many of the lower branches die leaving rather conspicious leafless stems and twiggy outgrowths. Any branches, live or dead, which are removed should never be left as stubs but should be cut right back, flush to the

limbs from which they have grown. Cut surfaces should always be covered over with a suitable sealant immediately after the job has been completed. This is particularly necessary when dealing with cherry trees because they are exceedingly prone to silver, leaf infection.

There are a number of proprietary products on the market specifically prepared for treating pruning cuts, and some of them even contain a fungicide. Bituminous paint has also been found to be effective but needs to be applied with care so that it is not splashed about where it is not wanted. Autumn is the .time deemed safest for the tree from silver leaf infection. A special consideration is required for weeping

cherry trees. Over a ' period of years, growth can become so dense on top that all the under- • growth dies leaving a ; tangle of predominantly [ dead branches. This un- • sightly mess requires at- ■ tention, by which means it is possible to rejuvinate the tree. J Whatever the problem * any tree surgery should be;. tackled objectively and ef- >■- ficiently, and in such a; manner so as to retain or . reenourage the natural i growth habit.

GARDENING

g By

M.Lusty