Monday, September 26, 2011

Growing Fruit Trees – Zone Specifications Critical for Success

Growing fruit trees in the continental United States normally dictates that we plant deciduous fruit trees. An exception would be citrus fruit trees, which are grown in subtropical zones (zones 9 and 10), or in containers for inside temperature control. Nursery grown fruit trees are usually orchard quality trees that are grown by fruit growers and the backyard gardener for producing backyard fruit.

The zone in which the fruit grower is located is critical for success for the many fruit varieties that are offered. All nursery grown fruit tree varieties have zone recommendations on the tags or in the nursery advertisements. Zone specifications are just as important to the backyard fruit grower as the professional orchard fruit grower.
Most subtropical fruit trees are evergreen. The subtropical fruit trees will withstand some below freezing weather if they are in their dormant season or semi-dormant season. In temperate climatic zones, the fruit grower will need to move the citrus varieties inside during the winter months. Temperate zone fruit trees would include apples trees, cherry trees, pear trees, and peach trees. Subtropical fruit trees would include orange and lemon trees.

Caring for fruit trees is much the same as caring for any plant. Proper soil, drainage, moisture, and fertility conditions would need to be maintained. Proper care for the fruit bearing branches is unique as compared to other trees.

 Pruning fruit trees should begin at an early age. Most fruit trees produce more quality fruit, and live longer, healthier lives if properly maintained and pruned. Fruit tree pruning does not need to be complicated or confusing. Many times the nursery will do the initial pruning on the dormant fruit tree. If the fruit tree arrives already pruned from the nursery, it can be planted without further pruning.

If the dormant bareroot tree arrives with long branches and over 3 foot tall, prune the tree to knee high and cut the side branches back by at last 2/3rds to promote vigorous new growth. Top pruning induces lateral branch growth, and in fruit trees, this produces a more easily accessible tree branch and shapely form. Pruning also diverts the expenditure of nourishment to form woody growth to that of buds and fruit.

Fruit trees are fast growing. After the spring flush of growth, cut the new growth back by ?. In late summer, prune the new growth on the branches back again by ½. The 2nd year pruning of the backyard fruit tree is the same as the first. Cut back new growth by half in the spring and again in late summer. In the 3rd year, choose a height and do not let the tree get any taller.

Tree height is a decision for the pruner. When there are vigorous branches above the chosen height, cut back or remove them. I n late spring or early summer, pinch back all new growth. Size development and low fruiting wood is determined in the 3rd year. Each branch should have at least 6 inches of free space around them. Remove all crossing branches that are too close together. Keeping fruit tree branches open to allow more light and freedom for bee movement is important. Sunlight and bees carrying pollen should allow for more and larger fruit. All varieties of fruit trees can be maintained at a predetermined height if pruned consistently.

 Pollination of backyard fruit trees is just as important to the small property owner as it is to a professional nursery. Many varieties of fruit trees are not self pollinating and require another fruit tree for pollination. Every fruit tree needs pollen to set fruit regardless of zone. Nursery grown apple trees will have pollinators by every row of apple trees. Even if the apple tree is known as self-fruitful, pollen from other compatible apple trees can assist in setting more fruit. Cross pollinizing varieties should bloom at approximately the same time as the other apple tree.

Crabapple trees are exceptional pollinizers because of their heavy blooming characteristics and their length of bloom period. Other fruit trees, such as sweet cherries, need pollinizers to produce fruits. Sour cherry trees are mostly self-fruitful. Many peach, pear, and plum trees are self-fruitful and will benefit from having a compatible pollinizer close by. Lemon and orange trees are mostly self-fruitful.

Citrus Trees

Citrus is thought to have developed in Southeast Asia in about 4000 BC. Citrus probably entered Europe after the fall of the Roman Empire. Citrus fruits were first brought to America by the Spanish and the Portuguese. The fact that citrus trees are evergreen and cannot tolerate freezing dictated that the warm climates of Florida and California became the leading citrus producing states in the Unites States. Citrus fruits belong to the ‘Rutaceae’ family. Citrus fruits are fragrant, with or without seeds depending on the variety, and contain significant amounts of vitamin C, pectin, and fiber. They are fat free, sodium free, and cholesterol free.

The dwarf citrus trees offered by Nature Hills may also be grown inside. Dwarf citrus trees in containers can be successfully grown throughout the United States. Citrus like 8 to 12 hours of sunlight a day. Full-spectrum fluorescent grow lights are the best supplement for inside growth. They will tolerate less light in the winter than in the spring and summer. For container soil, use a light, well draining commercial soil mix. Do not put gravel in the bottom of the pot. Place the container on pebbles in a saucer or other surface that will allow air and water flow. Water them every 5 to 7 days with ¼ to ½ gallon of water. Do not keep them standing in water. The soil should be moist, not soggy. Citrus foliage benefits from being sprayed or misted with water, especially in winter months when the humidity might be low. A humidifier would also help keep the leaves lush and healthy.