Your trees don’t need much care in the winter while they are dormant, but what little care they do need is important. Perhaps the most important care of the whole year that you can give your trees is a dormant oil spray during January or February. Dormant oil is highly refined petroleum which emulsifies when mixed with water. It can be used only when the tree is dormant. It is not a poison, but destroys the insects by smothering them with a coat of oil. The principal target of the oil is scale, but over wintering spider mites are also destroyed, along with the egg cases of numerous other insects.
Scale is a tiny insect a couple of times larger than the period at the end of this sentence. They are often discovered by unsuspecting owners when their tree dies. The scale insect secretes a shell (under the microscope it is shaped like a Chinese coolie’s hat) that protects it from other predators and insecticides. Thousands of them may coat the tree in a solid layer. Once attached to the tree they suck the juices and the life out of it. You can find them by scratching the bark with your fingernail, which will dislodge them. There will be a tiny red spot where they were attached and the wood in that area may have a reddish cast. If you don’t find any, then you need only one dormant oil spray. If you find them, then a second spray in two weeks is advisable. If you have a bad infestation of them you can mix an insecticide into the sprays and the dormant oil will be more effective. Apply a heavy coating of oil, paying particular attention to the trunk area all the way down to the soil.
For folks in warmer climates growing the low chill Anna and Dorsett trees—neither of these varieties drops their leaves very readily. An oil spray in January will take care of the insect problems and help defoliate them at the same time. If it is plausible, you can also pull the leaves off by hand. Last year’s leaves are a source of disease for next year’s crop.
Pruning Your Tree
The time to prune is while your tree is dormant, January or February. During this period the nutrients of the tree have gone down into the root system, leaving the wood above ground quite dry, which protects the tree from freeze damage (splitting of the wood as the sap freezes). Removing wood from the tree now is actually stimulating to the growth of the tree. Pruning wood from the tree when it is actively growing removes nutrients and is weakening.
Basic Things Accomplish by Pruning:
- Control the size of the tree by cutting the branches off as high as you can reach every winter. By doing this, you will be able to touch every leaf on every tree and will have total control of them. No ladders are needed during harvest—all the fruit can be picked from the ground. Over a period of years the wood that is not pruned gets bigger and stronger every year, and that is the part of the tree that produces the fruit. Each year this is repeated, and each summer it re-grows. The top growth does not produce fruit, but manufactures carbohydrates for the tree and shades the fruit. To show it your appreciation, cut it off again next winter.
- Increase the size of your fruiting wood by cutting off about 1/3 of the long, slender branches. Apples that grow on the tips of the small wood will weigh the branch down and cause a number of undesirable things to happen. By removing the tips, you insure that the fruit will grow on wood strong enough to support it. In a few years the tree will have lots of strong wood developed in the area of the tree that produces the most fruit and will be ready for serious work.
- Remove any bad branches by cutting them off at the trunk, Bad branches are those that are growing downward, or are directly below a nearby branch and being shaded, or those from a tree that is getting crowded inside and simply needs to be thinned.
Above all, don’t be shy about cutting on your tree. A few well chosen cuts are very good for it. Most people don’t recommend painting of the cuts with a sealer, but do it if it makes you feel good. Large cuts of an inch of diameter or more should be sealed.