Question: Is July a bad time to prune our maple and dogwood trees? How far back should we prune our Wisteria shoots? Audrey, Phoenixville, PA
Answer: Audrey, the practice of summer pruning has long been used. This is the best time to prune trees that would bleed if pruned earlier. Maples, dogwood, birch, yellow wood and horse chestnut should be given this attention now. Summer pruning has the opposite effect of spring or late winter pruning since subsequent growth is short and tends to favor flower and fruit formation.
Spring pruning forces much vegetative or leafy stem growth which is not fruitful. Fruit trees and vines like wistaria which do not flower or produce fruit will sometimes do so if subjected to a systematic summer pruning. Larger plants may be dwarfed by summer pruning and their dimensions controlled. Large trees such as oak, maple and others can be kept low and shaped to any form.
Pruning Wisteria
The long shoots of wistaria which grew this year should be cut back to the third leaf. Subsequent shoots are also cut back. On fruit trees, the long over-vigorous stems are cut back to at least two-thirds their length and all suckers are removed. This is especially helpful if, after spring pruning, the tree is carrying too much vigorous growth. This is the method which is followed with espalier fruit trees.
If large limbs are to be removed in pruning shade trees, be careful that the bark is not stripped off the trunk in the process. Make two cuts, one underneath the limb some 18 inches from the trunk, the second on top 12 inches from the trunk. The branch will snap off leaving a stub which can be sawn off close to the trunk. All cuts over an inch in diameter should be covered with regular tree wound paint. Don’t use any other kind of paint.
Mid-Summer Moisture Required
Midsummer brings with it the problem of supplying enough moisture to support continuous growth. Food materials in the soil, whether from fertilizer or other sources, cannot be used by the plant roots unless there is plenty of moisture. Vegetables, flowers, roses and all such fast and continuous growing crops must have water in quantity.
When applying moisture, water deeply, do not merely sprinkle. Conserve the moisture you apply. You cannot keep the plant from throwing off moisture but you can stop evaporation from the soil surface. Cultivating leaves a loose layer of soil and helps break the contact between the soil below and the air. A cover mulch, using whatever material is available, is far more effective. Leaves, grass and weeds that have not formed seed heads are best as they gradually decay and add organic matter to the soil. If sawdust, shavings or similar hard materials are used, apply a sprinkling of fertilizer. There is the danger of starvation from loss of nitrogen when these materials are used.
Lawns
Raise the blades of the lawn mower to avoid cutting the grass short in July and August. Heat slows up grass growth. If it is too short, the roots may be both burned and starved and bare areas which appear will soon become filled with crabgrass and other weeds. When water is needed, soak to a 6-inch depth.
If the lawn is infested with weeds, begin a campaign to eliminate them. too. Use care in applying the weed killer… read the label and apply as recommended. Wind can carry sprays to ornamental plants and cause much injury.
Climbing Roses
Climbing roses are pruned after flowering, which is just the reverse of what is done with bush roses pruned in spring before flowering. Climbing roses flower on the canes produced last year. So, in addition to the flowering canes, you will find numerous new canes beginning to grow. Generally, the flowering canes are removed entirely and the new canes are tied in for next year: This does not mean that the older canes will not flower again but the plant should be kept down to some manageable size by their removal. Then, too, the best flowers are produced on the newer canes of some varieties, especially the ramblers.
There is a type of climbing rose which flowers better on the older canes. This is the large-flowered climber. If canes are left to grow they will climb to the top of the house. Some large-flowered climbers do not send up many new canes each year as do the ramblers. Pruning here consists of cutting out the side shoots that grow from the main canes. The shoots are reduced to three leaves. The main stem can be retained for a number of years and there will be fewer bothersome shoots from the base.
