Peach trees grow about 18 feet tall and require a good deal of pruning to encourage new growth on which the fruit is borne. Once a portion of branch fruits it will not bear fruit again.
Varieties The following varieties can be expected to do well in Michigan.
Fairhaven - Good for freezing, freestone. Garnet Beauty - A semi-freestone peach. Susceptible to bacterial spot. Golden Jubilee - Self thinning and hardy, freestone. Redhaven - Freestone, highly recommended, good for freezing. Reliance - Large, freestone fruit. Sunhaven - Medium-large freestone fruit borne on a vigorous tree.
Glohaven - Large freestone fruit good for canning and freezing. Halehaven - Medium large freestone fruit but susceptible to brown rot. Loring - Medium sized freestone.
Cresthaven - Medium-large freestone fruit good for canning and freezing. Elberta - Large freestone fruit, resistant to brown rot.
Bonanza - Medium-sized fruit. Plant can be 6 to 8 feet tall. Compact Redhaven - Grows 10 feet tall but is otherwise similar to Redhaven.
Nitrogen is the most important nutrient in fruit production and is usually the only fertilizer element that should be applied annually. Trees need sufficient nitrogen to insure optimum growth and production. Too little may result in low yields, poor fruit size, and excessive cold injury. But too much may result in excessive growth, poor fruit color, and excessive cold injury.
The amount of nitrogen to be applied to a peach tree should be based on the previous growth and performance of the tree. Young peach trees should not make more than 18 to 24 inches of new terminal growth annually; 12 inches is sufficient to maintain mature trees in good vigor and full production.
In general, a mature bearing tree will need about one pound of actual nitrogen per year. Nitrogen should be applied in late fall after leaf drop, or before growth starts in the spring. Do not use Urea as it will injure peach trees
Potassium is the only nutrient element, other than nitrogen, that is frequently deficient in peach. Potassium deficiency reduces tree growth, yields and fruit quality. The leaves of trees with this deficiency are smaller than normal with chlorotic or "burned" margins. And, the leaves may be rolled and crinkled on the edges. Potassium in the form of potash (K2O) may be applied in the spring or fall. The most common potassium fertilizer is muriate of potash (60 percent K2O).
Amount of Thinning
The amount of thinning the tree should have depends on other cultural factors which influence the tree's vigor and ability to produce. Some of the thinning may have been done by moderate or heavy pruning. This is particularly true if the tree has had detailed pruning with careful attention to the removal and spacing of fruiting branches or twigs. If the tree has been lightly pruned or not pruned at all, much heavier fruit thinning is needed. In general, thinning should take into account the tree condition, past yields and future performance. Thinning should be tied, if possible, to the leaf surface on the tree. About 50 leaves per fruit are needed for development of fruit with good size and proper quality. The leaf area does not always need to be adjacent to the peach. The sides and tops of most peach trees can carry many more fruits than the bottom inside areas of the tree. Thus, the whole tree should be considered rather than the simple removal and spacing of fruits on individual twigs or branches. In the case of freeze damage, lower areas of a tree may not have any fruits; therefore, the upper areas may be left with more fruits than when no freeze damage occurred.
The amount of thinning also depends on the variety. Such varieties as Redskin, Sunhaven and Redhaven need more thinning and better spacing of the fruits than such varieties as Richhaven and Elberta.
Probably the best method of thinning peaches is by hand. This is the only way by which the fruits can be spaced at a standard distance, (usually 6 to 8 inches) and all unwanted fruits can be individually removed.
Mechanical Thinning Aids
Various kinds of poles and rubber hose attachments have been used in recent years for thinning peaches. The labor cost is usually about half that of hand thinning alone. The peaches are knocked off by striking the branches a short distance below the fruit clusters. Pole thinning has worked well on varieties maturing in mid- season or later. It has been most effective where the poles were used to take off the bulk of the fruit quickly, after which hand thinners followed up to finish the trees.
Injury Caused by Low Temperatures
Cold injury, sometimes called winter injury, might be described as injury to wood and dormant flower buds by low temperature, as compared with "frost" injury which is usually restricted to opening flower buds or blossoms. Cold (winter) injury, however, is a broad term, and injury of this type may occur in the fall or spring. In fact, one of the greatest peach tree kills on record was the freeze of October 10, 1906, when very late maturing peaches were still on the trees.
The results of cold injury are very apparent -- even spectacular -- when a peach crop is lost because all the flower buds are killed, or the trees themselves are killed, by one extreme drop in temperature. Of almost equal importance, though less noticeable, are the minor injuries in the tree which provide an entrance for the peach borer and the destructive peach canker disease, which, working together, considerably shorten the life of the tree. Spring frosts can be destructive, but seldom cause serious damage in Michigan peach orchards in comparison to peach-growing areas farther south.
Care Of Trees Severely Injured By Low Temperatures
Sometimes temperatures drop so low in fall and winter that severe injury to the wood of peach trees occurs. Injured wood will show discoloration. Slightly injured wood will be light brown or amber. Severely injured wood will be very dark, almost black. Suggestions for handling severely injured trees are as follows:
1. Delay pruning until growth starts. Then remove only dead wood. Make no large pruning cuts. 2. Do not use oil sprays on injured trees. 3. Apply nitrogen fertilizer before growth starts. 4. Protect foliage from diseases and insects. Do not omit the leaf-curl spray. Protect young trees against cutworms. 5. Give trees good cultural treatment. Keep weeds away from young trees. 6. If bark splits, tack it down at once and paint with tree paint. Dead areas should be cleaned out and covered with tree paint. 7. Do not be hasty in removing injured trees. Give them good care and see what they can do for themselves.
The open center method is used on peaches. At planting time, head back the one year old trees to 18 to 24 inches. Two or three weeks after planting, remove all the shoots except for those to be saved for scaffold branches. If the trees planted already have branches, select scaffold branches as described below.
Scaffold branches should be well placed on all sides of the trunk and as near as possible to the place where the tree was cut back at planting. Two weeks after selecting scaffold branches, inspect the trees and remove any shoots that have formed. In the spring of the second year, remove any shoots that will not be used as scaffold branches. Cut the scaffold branches back to equal lengths.