Bonsai Shaping: Maintenance Pruning

Maintaining the shape of your bonsai with maintenance pruning is at least as important as formative pruning, since it also makes a day-to-day contribution to the effort of producing a bonsai of a particular style.

Maintenance pruning will vary, since any tree could be pruned several times during its growth. There are several different pruning methods that suit different species and cultivars of trees and you should follow the correct one.

In general terms, pruning for care and maintenance is intended to restrict the irregular growth resulting from the natural development of the tree. It is intended to promote harmony between the trunk and the branches and their foliage, which is essential to obtain a tree worthy of the name bonsai. Pruning for care and maintenance is repeated throughout the growing season to reduce the number of new branches by disbudding, to reduce the size of the leaves by trimming them and to shorten the shoots to inhibit their growth. This is an indication of the amount of care bonsai require for a large part of the year.

this bonsai needs pruningDEBUDDING:

This type of pruning is only for deciduous trees. Pinch the buds out with your fingernails when the first growth appears. This is normally done at the beginning of spring, although it may be done several times during the year on some trees (e.g. elm, maple, hornbeam). When carried out repeatedly it produces smaller leaves. The tree may be affected to some degree and so should be fed regularly with modest amounts of fertilizer.

TRIMMING LEAVES:

This mainly concerns trees with broad leaves, like chestnuts and oaks. Clip the leaves down by a half in late spring. Leaves clipped like this will drop off and be replaced with smaller leaves during the summer. Deciduous trees with small leaves can have their leaves completely removed (heavy pruning), the operation being repeated several times in the growing season. This is a radical practice which should only be carried out if the tree is quite healthy and vigorous.

CUTTING OR PINCHING BACK SHOOTS:

Once it has been pruned, the good proportions of the tree are restored. Pruning can he done several times in the growing seasonThe most important maintenance operation on bonsai, since the quality of the tree’s foliage largely depends on this. Pinching back helps preserve shape, by inhibiting the natural exuberance of the growth. The method may differ from one species or cultivar to another, depending on whether the tree is deciduous or a conifer.

PINCHING BACK DECIDUOUS TREES:

How often this is done depends on the growth rhythm of the tree. For a maple, it will be repeated several times in the season, whereas a hawthorn may require pinching back twice only, in early summer and early autumn.

The technique is roughly similar for all species. It consists of nipping the shoots above a leaf joint, always leaving a pair of leaves on the branch. This operation will allow the branch to ramify and at the same time dwarf the new leaves. This method also encourages good sap circulation, called upon by the requirements of the branch. It goes without saying that flowering or fruiting trees should not be clipped until after flowering or fruiting has finished.

Always collect the leaves you have cut. If you leave them lying around, the plant will look unkempt and the decomposing leaves will keep the soil damp and favour infection by fungal diseases.

WATCH OUT:

Take care not to hurt yourself, because some conifers, in particular, have very sharp needles. If you are late pinching back, the needles may have hardened and could hurt you. Be careful not to prick yourself. Where there is any risk of injury, use scissors rather than fingers.

PINCHING BACK BONSAI CONIFERS:

While the reasons for doing this are the same as for deciduous trees, the technique is considerably different. First of all. It is carried out just once a year, generally in mid-spring, when the young shoots start to sprout. In most cases it is sufficient to remove one third of the shoot with the fingers. Do this by pulling lightly and the shoot should come away easily.

Do not use scissors, for fear of cutting the ends of the remaining needles which could then turn yellow a few weeks later. Whereas a pine shoot should only be lightly pulled, it is necessary to twist shoots of a spruce as well. Unlike the other conifers, the juniper should be pinched right back throughout its growing season, which lasts from mid-spring until mid-autumn.

SOME EXAMPLES OF PRUNING AND PINCHING

Tree

Pruning or pinching technique

Time of year

Pinu.s thunbergii (Japanese black pine)

Prune the shoots

Early to mid-summer

Abies spp. and cvs. (spruce)

Prune half of all 2 cm (3/8in) long shoots

As shoots appear

Juniperus chinensis (Chinese juniper)

Pinch out almost all shoots

Repeatedly from spring to autumn

Juniper us rigida var. nipponica (needle juniper)

Debud completely

As buds appear

Acer spp. and cvs. (maples)

Clip leaves (leave one pair at each point) and debud

Repeatedly from spring to the end of summer

Ulmus spp. and cvs. (elms)

As maples, above

As maples, above

Fagus spp. and cvs. (beech)

Prune branches and leaves, leaving one or two pairs

Repeatedly from spring to the end of summer

Fruit trees in general

Pinch back shoots to two buds alter flowering

Mid-summer

Pyracantha spp. and cvs. (firethorn)

Pinch back new shoots, to two pairs of leaves

Mid-spring

14. March 2012 by Dave Pinkney
Categories: Bonsai, Training/Pruning | Tags: , , , | Comments Off on Bonsai Shaping: Maintenance Pruning

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