Guide to Tree and Shrub Care in Early Winter

Jobs to do

Preparing the soil for planting

Early winter is usually a good time to do some basic digging of previously uncultivated soil or to improve badly structured soils. These include those which are markedly quick-draining, such as chalky, sandy and shingly soils or heavy and water-retentive ones, such as sticky clay, peat and silt. To grow plants successfully in these soils, it is advisable to dig them a few months in advance of planting, mixing in soil improvers, such as rotted organic matter, coarse sand or grit, peat, and lime if very acid. The soil should be dug to a depth of two spades, the bottom of the hole or trench forked up and mixed with rotted manure, garden compost or similar material and the soil, together with the soil improvers, returned. The top spit should be kept separate from the second, so that they can be returned in order, and unmixed.

If lime is thought to be necessary, to break up a heavy soil or to decrease extreme acidity, it should be mixed in some weeks after adding organic matter, otherwise a chemical reaction occurs which results in loss of nutrients from the soil.

Once the soil has been roughly dug, it can be left until early spring before doing the final preparation for planting.

Planting

General planting can still be done in early winter, if not finished in late autumn but never when the ground is frozen or waterlogged.

Pruning ornamentals

If the large-flowered and cluster-flowered roses have grown rather leggy, it does no harm to shorten them back a few centimetres (inches) to prevent wind-rocking.

Shrub roses can also have done what little pruning may be needed, to tidy their outlines. Remove old growth and any shoots which are badly diseased or cluttering up the bush, preventing the good new growth from getting the light and air available.

Wisteria which was partially pruned in summer can be finished now by cutting back the shortened shoots to leave 5 or 7.5cm (2 or 3in) of stem. This method of pruning gradually builds up a spur system, and in time a few of the oldest spurs should be cut right away, once they begin to flower badly.

Climbing honeysuckle can be thinned now by cutting one or two of the oldest stems right out, and removing dead, diseased and weak shoots.

Campsis is mostly spur-pruned, with the new shoots cut back to stumps like wisteria, once the main shoots have filled the space allowed, but about four or five strong new shoots are left full length to clothe the support, and plant.

Summer-flowering jasmine can be treated now, if missed earlier but in cold districts, it is better to leave it until spring.

Pruning fruit

Once the leaves have fallen and the trees have become dorm-ant, pruning can safely be done, even in frosty weather, provided it is not severely cold.

Trees which were framework-grafted in the spring should be pruned by cutting the new growth from the grafted shoots at the ends of the main branches by a quarter to one third its length; one third of the remaining new shoots, spaced evenly over the tree, should be cut to about half their length, and any further sucker growth or badly placed grafts should be completely removed. In future winters, renewal prune in the usual way, as for bush apples and pears.

Apples and pears

Apples and pears, cordon- and espalier-trained – The new shoots partially cut back in summer can now be shortened to about 7.5-10cm (3-4in) if they are primary side-shoots, but if secondary, should be reduced to about 2cm (1in). The leading shoots should be kept cut back, if need be, to the space available.

Apples and pears, bush trees

The most productive method for the amount of labour involved is the system of pruning called renewal, based on the fact that a shoot will fruit in its third year. The object of this pruning is to get a good supply of new side-shoots growing all the time to replace, or renew, the fruiting wood.

At the end of the summer a new shoot will have leaves all alone it. During the following summer — the second one — buds will grow in the axils of these leaves; they will be round and fat, and are blossom buds. At the same time the tip bud will grow out to produce a new length of stem. In the third summer, the blossom buds will flower and fruit, growing out as they do so on a short length of stem, the beginning of a spur. The second summer’s new growth, at the tip of the shoot, will form blossom buds, and at the same time, its own extension of the stem at the tip.

By cutting back the two-year-old growth and three-year-old growth, the amount of fruit produced can be manipulated and the production of vegetative growth regulated, so that there is a balance in the tree each season between fruit and shoot production. Heavy cutting encourages shoots to form and takes away potential fruit; very light pruning can result in over-cropping and no renewal of shoots.

Depending on the vigour of the tree, about one-third to a half of the two- and three-year-old shoots can be cut, to leave about four or five fruit buds on the two-year-old growth, and one fruit bud or spur on the older. The growth at the ends of the main branches, the leaders, is pruned by one-third, a half, or two-thirds, depending on whether it is strong, moderate or weak, until its full length is reached. Then it is treated like a side-shoot.

The weather, the soil, the feeding programme, the root-stock and the variety will all affect the fruiting potential of the tree; if you find that the amount of pruning you are doing each winter is producing too much fruit or too much leaf, it must be adjusted, remembering that the more pruning, on the whole, the less fruit and the more shoots.

Apricots, fan-trained

Most of the pruning for these is done in spring and summer, but after fruiting or in early winter, one or two of the oldest main branches can be taken away completely, not necessarily every year.

Morello cherry, fan-trained

Cut very long bare shoots, which have been fruiting badly, back hard to a conveniently placed dormant bud, untie the remaining shoots, and re-tie, evenly spaced. Cut out any of these which are crowded.

Figs, fan-trained

Little needs to be done to figs in winter. New growth is constantly required for fruiting, so two or three of the oldest branches forming some of the ribs of the fan can be cut right down to leave stubs with dormant buds on them. Any shoots with long bare sections which are unlikely to be covered by other new growth are cut to below the bare section, and new shoots should appear from the remaining stem.

Grape vines, wall grown

Once the leaves have fallen, vines can be pruned by cutting the side-shoots back to a stump with one or two buds on it, and the topmost leading shoot back by about two thirds.

Medlar, mulberry and quince

Virtually no pruning is needed for these fruits, beyond the standard treatment of clearing out weak, crowded, dead, diseased or crossing growth. All will fruit satisfactorily without further cutting.

Peaches and nectarines, fan-trained

These can be pruned immediately after picking the fruit, or after leaf-fall. The shoots which have fruited are cut back to the replacement shoot and each of these spaced out regularly and tied to the wires. If crowding is unavoidable, some thinning of these shoots can be done.

Saving scions

If you are proposing to framework-graft apples or pears in the spring to change the variety, the one-year-old snoots cut off in the course of renewal pruning can be used as scions. They should be strong and mature. Heel them in, tied in small bundles, about 15cm (6in) deep in a trench on the north side of a fence or wall; label them securely.

Protecting

From now until spring, it will be necessary to keep an eye on supports and protection of tender plants, climbers and those which are favoured by birds. Plants vulnerable to cold, especially north and east winds, are: Abelia grandiflora, campsis, ceanothus, Clematis armandii, eccremocarpus, escallonia, fremontodendron, fuchsia, hebe (some), hibiscus, summer jasmine, Mexican orange blossom (choisva), phlomis, piptanthus, privet, rock rose (cistus), romneya, Senecio greyi, solanum and yucca. All these need some sort of protection.

Weather damage can be in the form of rocking, when hollows form round the trunk or stem bases, which fill up with water and rot the bark, or plants being lifted by frost after planting. Snow and wind can break shoots and branches; bark can split due to cold (cover wound with sealing compound or glasshouse sealing tape), and young shoots are burned by strong cold wind.

Protection against birds may be destroyed by the weather, so renew sprays after heavy rain or snow and make sure that netting is still tightly secured and without unwanted holes after wind.

Sweeping up

Leaves may still be in need of sweeping up, after a late fall, or burning, if diseased.

Increasing

When pruning vines, cuttings can be made and used now or stored for increase later. Mature one-year-old shoots are used, to provide cuttings about 30cm (12in) long; these are put in to half their length in a sheltered place outdoors or in a cold frame. In good conditions, these will root without any further ado, but if not, they can be used to provide vine ‘eyes’ in late winter.

Treating pests and diseases

Once the pruning is finished, tree and climbing fruits can be winter washed if necessary.

To prevent rose black spot and rust overwintering, as far as possible, leaves, fallen shoots and flowers should be raked up from round the plants and burnt. If the large-flowered and cluster-flowered roses are fully dormant, they can be sprayed with a solution of Bordeaux mixture, but it should not be applied if there are still leaves on the plants.

Vines should be brushed down thoroughly with a stiff brush before spraying or painting to get rid of loose bark in which pests and diseases can lurk.

30. August 2011 by admin
Categories: Trees and Shrubs | Tags: , , | Comments Off on Guide to Tree and Shrub Care in Early Winter

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