Winter Tree Trimming and Pruning
Winter pruning is a steal because it makes use of hours otherwise unlikely to be spent in effective outdoor gardening. In gardening currency an hour in spring is worth several winter hours because after growth starts in spring the number of tasks that demand attention is overwhelming. In most sections of the country warm spells occur during the winter when the temperature is sufficiently high to make winter pruning practicable.
Some trees, shrubs and vines actually respond better when pruned in winter. Others prosper equally well with either spring or winter pruning, but, generally, slightly tender species and varieties are likely to be harmed by winter pruning. The list of these varies according to locality.
As used here, the term winter refers to the period that extends from the time the plants go dormant in the fall until their buds begin to swell in spring in response to rising sap. Pruning done after the leaf buds begin to swell is considered spring pruning.
For the plant’s benefit, winter pruning should not be done for two or three weeks after leaf fall nor for about the same period of time before the buds begin to swell in spring. By not pruning during these periods, the plants lose a minimum amount of stored foodstuffs.
Grape Vines and Fruit Trees
Grape vines and fruit trees are the plants most commonly pruned in winter. It is especially important to prune grapes in winter because if the operation is put off until early spring they “bleed” profusely. Several well-defined systems of pruning grapes are described in books on viticulture, but for most gardeners the Kniffen system, or some modification of it. is best.
The four-cane Kniffen system produces a vine which at maturity consists of a vertical trunk that reaches the upper of two horizontal wires 30 inches and 60 inches above the ground stretched between posts. Extending from the trunk in each direction along both wires a cane of the previous year’s growth is tied at pruning time.
From this cane fruit-bearing shoots will develop. Near the base of each cane a renewal spur (a cane cut back to two buds) is allowed to remain. Pruning consists of removing as close to the trunk as possible all two-year old wood and the previous year’s canes except those selected to be tied to the wires.
They are then cut back so that the vine after pruning carries a total of from fifteen to sixty (occasionally a few more) buds, depending upon the vigor of the vine.
With grapes grown on arbors and trellises the objective is to establish a well—disposed framework of rather widely spaced permanent trunks and branches (one or more trunks to each vine). Canes of the previous year’s growth are selected to fill in the spaces between the basic framework; they are shortened to two to four feet and the remainder of the previous years growth is cut away.
The size of the bunches and the quality of the grapes depend largely upon the number of bunches the vine carries in relation to the ability of its roots to provide moisture and nutrients. Light pruning therefore makes for more and smaller bunches, heavy pruning for fewer and larger bunches.
Overgrown and tangled vines may be brought under control by gradually removing excess trunks and branches over a two or three-year period.
Pear Trees
Pear trees are never pruned more than is absolutely necessary since the danger of fire blight gaining access through the wounds is always present. Confine pruning primarily to removing diseased and broken branches, and, as in all pruning of trees, it is an excellent practice to protect the cut ends of all branches that measure an inch or more in diameter with a special tree-wound paint.
Apple Trees
Apples are pruned to develop a system of scaffold (framework) branches so disposed that they do not cross each other and can receive light and air. The best general method of training is the modified leader system which makes a more open-centered tree than the central leader system formerly favored.
Here is how to develop a modified leader tree. For the first four or five years of its life a central trunk is permitted to develop and from it the scaffold branches mentioned earlier are trained, the purpose being to retain a framework of well placed branches of varying diameters that leave the trunk at wide and strong rather than narrow and weak angles.
Trees which bear but are not yet mature are pruned each winter to keep their branches. adequately spaced, to keep the interiors of the trees open for easy spraying and to maintain a balance between the amount of fruit the tree is allowed to carry and the root system that must supply nutrients and water for it.
Pruning mature apple trees calls for taking out broken and badly diseased branches and thinning out crowded wood. Sometimes it is desirable to lower the height of a tree by heading back the branches quite severely and it is wise to do this gradually over a period of two or three years rather than to cut the full way back at one time. It is best not to lower the height of a tree more than about four feet a year.
Peaches
Peaches may be pruned in winter and a good form to develop is the modified leader mentioned for apple trees. Peaches bear fruit on new growth, so as much of the previous season’s growth as possible is removed each year without disturbing the essential framework. Unlike apples, neglected overgrown peach trees may be headed back severely at one time.
Lopping shears are the most efficient tool for removing branches too heavy for pruning shears and not large enough to require the use of a sharp saw.
Cherries and Plums
Cherries and plums, compared with apples and peaches, require little pruning which for the most part consists of thinning and the removal of dead, broken or diseased wood. Shade trees such as oaks, elms and lindens are practicably winter pruned. Because of the more alarming than harmful loss of watery liquid from newly-cut surfaces of such “bleeders” as maples, yellow-woods and birches in late winter and early spring, it is often better to do whatever pruning these need in summer.
The objectives in pruning young shade trees are fairly obvious. You want to encourage the development of a framework that does not have weak crotches or crossing branches. In most cases try to retain a central leader by suppressing all but one of the competing leaders that may appear. Sometimes you prune away their lower branches so you can walk beneath them.
With older shade trees pruning consists of the removal of dead, damaged and diseased branches, possibly the cutting off of branches that interfere with telephone wires, buildings or views or which are weak and subject to storm damage.
As far as possible the natural habit and outline of the tree in question should be preserved. Work in big old trees is often hazardous and because of the size of the
branches, special equipment and techniques are required in pruning. For safety’s sake and for the health of the tree it is work best left to the professional tree surgeon.
Spring Flowering Shrubs
Spring flowering shrubs gardeners have long been told, are not to be pruned until immediately after they flower. This is generally true, but there are exceptions to the rule. For example on those shrubs that provide branches which can be placed in containers of water and forced into early bloom indoors, such as forsythia, bush honeysuckle and flowering quince, it is sound practice to prune them in winter if the cutting is done in such a way that they are thinned advantageously.
Then too, spring-flowering deciduous shrubs that have become badly overcrowded and are tangles of growth can be rehabilitated by drastic thinning and the cutting back of long unwieldy branches. In thinning, remove ill placed, crowded, weak and diseased branches. There is no better time to detect them than when the shrubs are leafless in winter.
Summer Flowering Shrubs
Summer flowering shrubs or those which bloom in fall may be pruned in winter to whatever extent may be desirable. Retain the natural outline of shrubs in thinning and save the new, robust stems. Never shear off the top of a shrub.
Long-handled saw enables you to prune without climbing in tree. Also handy are shears attached to a long pole and operated by the pulling of a ropes
Evergreens
Evergreens as a general rule are never pruned in winter, but a little judicious cutting of hardy types such as yews, pines and even holly to supply a little material for interior decoration may do no harm.
No matter what plant you prune, you should make each cut with a definite purpose in mind and with knowledge gained through experience of what is likely to happen growth wise as a result of the cut. Do not make the mistake of just pruning for pruning’s sake.
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