On pruning...

I just recently compiled a pruning report a lot of people have told me they found useful, so please, enjoy!

Pruning consists of the removal of a plant part or parts to improve the health, appearance or usefulness of the plant. Pruning provides the means of preventing, correcting or improving undesirable growth. But, failure to use recommended techniques often leads to despoiling a tree or shrub. For instance, there are some who feel that unless a large brush pile is created, the job is unfinished. At the other extreme, there are those who feel that a plant will be damaged if even the necessary amount of pruning is done.

In order to prune correctly, consideration should be given to such factors as the rate and habit of the plant's growth, specific pruning techniques recommended for the plant, and the desired end result.

Pruning is work, and the trend in modern gardening appears to be toward a reduction in maintenance. The necessity for pruning can be considerably reduced by selecting the proper tree or shrub for the location. Those which are not entirely hardy, or which will grow too large for the location, or tend to be vigorous and become quickly overgrown, or are inclined to have a lot of dead wood or become unsightly with age, should be kept to a minimum in the landscape plan. The wide availability of many plant types in nurseries today has enabled the home-owner to consider these factors when buying plants. Thus, proper selection of trees and shrubs can minimize the need for pruning.

Here are some of the specific situations which good pruning practice can solve:

1. Control of undesirable habit of growth.

2. Removal of dead, broken, or disease- and insect-infested branches.

3. Inducing more compact and sturdy growth by removal of certain branches even though healthy.

4. To produce a desired formal shape or size.

5. Improvement of flowering and fruiting by proper thinning or removal of old branches.

6. To better the chances of survival at transplanting time by reducing number or size of branches.

7. To retain maximum color in colored-twig shrubs by removing old branches.

The proper time of pruning is often a question and, in general, from the standpoint of plant growth, pruning can be done at practically any time of year. However, one must consider such factors as food supply, flowering period and winter hardiness. The operation can be harmful if new growth is removed in the spring. A deciduous plant manufactures food during the growing season, which is stored in various forms in roots and stems over winter. This food is the reserve energy supply for new growth and if the growth is removed before new food can be produced, growth may be stunted for the season.

With most plants, the ideal time to prune is during the dormant season before new growth starts. Some flowering shrubs are exceptions and this is indicated under the shrub pruning section.

The method of making pruning cuts is of great importance. Most rapid healing of a wound occurs when the cuts are made flush with the adjoining branch. When even small stubs are left, healing is prevented, the stubs die back and disease and rot organisms gain entry to healthy tissue. The same problem occurs when branches are broken instead of cut off. Cuts of terminal shoots should be made just above a bud. Proper care should be given to large pruning cuts to facilitate healing.

Breaking off the tip of a branch (pinching it), as shown above, stimulates the growth of more branches, as shown at the right, and prevents the plant from growing too tall.

The wounds should be shaped by carving to a point at top and bottom and all wounds larger than one inch in diameter should be covered with a tree wound dressing. House paints or paints with a lead base should never be used. "Tree paint" is available from all good suppliers to the horticultural trade.

The general procedure to use in pruning any plant is to follow this schedule:

1. Remove dead, broken, and disease-or insect-infested branches.

2. Remove branches, which cross or are detrimental to the shape and appearance of the plant.

3. Use the pruning procedures specified under the plant types that follow.

Specific procedures for pruning different types of plants are outlined under the following headings:

Pruning Established Plants Shade Trees

1. Remove branches interfering with foot or vehicular traffic.

2. Thin out top to open internal branches to light.

3. Do not cut central leader unless absolutely necessary.

4. If possible it is better to make two small rather than one large cut.

5. Call in a recognized arborist for work in high places: the chances are that you are neither trained nor conditioned to do high pruning.

6. To prevent tearing bark, cut any large branches as indicated in sketch.

Flowering Trees

1. Prune after flowering.

2. Follow recommendations indicated under shade trees.

3. Thinning top will increase flowering however, a heavy cut-back may reduce or eliminate flowers for a season.

Shrubs

1. Don't simply trim back top, thin out plant by cutting older branches back to ground.

2. Prune often and reduce necessity of heavy out back.

3. Some shrubs such as forsythia, mockorange, deutzia, and spirea can be cut back to the ground when it is necessary to rejuvenate old plants that have grown too large or are mostly "old wood."

4. In order to retain flower buds, shrubs such as forsythia, lilac, mock-orange and garland spirea should be pruned shortly after flowering.

5. On shrubs with colored twigs, such as red and yellowtwig dogwood, about one-third of the older wood
should be removed every year to retain maximum coloration.

6. Remove old flowers of shrubs such as lilac, rhododendron, hibiscus and magnolia to maintain optimum flowering for the next season.

Narrowleaf Evergreens

1. With the exception of pines, most narrowleaf evergreens should be cut back the desired amount in early spring, prior to growth.

2. When branches are cut back hard, leave some foliage on the remaining part. One exception to this is yew, which will grow from a severe cut back, though this is not generally recommended because the plants will
be unsightly for two or three years.

3. Pines are "thickened up" by pinching off part of each new shoot, the "candle" growth which comes from the buds at the beginning of the growing season.

4. Yearly pruning is required in order to maintain a compact habit.

5. It is common practice to shear evergreens with a hedge shear and thus obtain a severe, formal plant. More interesting, semi-formal plants can be obtained by pruning individual branches with hand shears.

6. Evergreens should be occasionally thinned out to open inner branches to light.

Broadleaf Evergreens

1. Relatively little pruning is necessary with plants of this type with the exception of rules 1 and 2 under general pruning recommendations.


Vines and Ground Covers

1. Some deciduous vines require occasional heavy pruning or complete cutback.

2. Prune vines to keep them out of windows or other similar areas on structures.

3. Ground covers may require pruning to keep them within bounds or to rejuvenate plantings.

4. Little pruning is necessary on many of the evergreen ground covers. Exceptions are some kinds of euonymus, English ivy, spurge, and creeping mahonia.


Roses

1. Follow rules 1 and 2 under general pruning recommendations.

2. Cut remaining canes back to 18 to 24 inches in height.

3. Prune hybrid teas, floribundas, and grandifloras prior to growth in the spring.

4. Prune climbers after flowering.

Hedges

1. Prune prior to growth in spring and again in summer to remove feathery new growth.

2. Prune annually to retain size and shape.

3. Prune to shape so that base of hedge is wider than the top. This allows light to reach the lower branches and prevents legginess.

Pruning Plants for New Plantings Shade Trees

1. When moving bare-root, prune broken and dead roots and cut back tops in proportion to the size of the root system.

2. When pruning the top, cut back lateral branches, not the terminal.

3. When moved with a ball of soil, only light top pruning is necessary or desirable.

4. Remove weak, V-shaped crotches when tree is young.

Shrubs

1. When moved bare-root, remove dead or broken roots, and cut back branches.


Evergreens

1. All evergreens should be moved with a ball of soil. Little or no top pruning is necessary.


Roses

1. Prune dead or broken roots.
2. Cut top back to 10- or 15-inch height.
3. Remove thin, spindly or crossing shoots.

Containerguy, thanks for all that info on pruning. I thought I had done wrong by pruning my spireas back after flowering but seems it was the right thing to do.
I have a clematis which I planted on a boundary fence and was always pruning backthe new tendrils during summer to keep it under control and only on my side of the fence! Luckily, as it is winter here now, it has decided to stop sending out shoots, so it and I are both having a rest.