From the Ground Up: Enjoy the fruits of spring labor

Spring is a good time to prune fruit trees. Pruning should be done before the fruit trees begin to break bud (leaf out) in early spring. Summer pruning of fruit trees isn't recommended, but water sprouts (rapidly growing shoots that develop just below a pruning cut) can be removed in June or July.

We are also close to the proper timing for use of dormant oil sprays. These are highly refined petroleum products that are mixed with water and applied to trees and shrubs to control aphids, spider mites and scale.

Proper timing is critical when using dormant oil sprays. In Iowa, dormant oils should be applied in late March or early April before trees show signs of breaking dormancy (before bud break). Dormant oils applied earlier are not effective as pests aren't actively respiring at this time. Dormant oil sprays should be applied as close to bud break as possible.

Some homeowners consider fertilizing fruit trees. Generally fertilizing isn't necessary in Iowa since most soils are quite fertile and can supply adequate amounts of plant nutrients to trees.

Monitor tree growth to determine whether fruit trees do need fertilization. Nonbearing fruit trees should grow 15 to 30 inches a year. Bearing trees should produce 8 to 15 inches of new growth (actual amount of new growth will vary due to differences in varietal vigor). Fertilization may be beneficial if the amount of growth is less than normal.

When fertilizing fruit trees, select a balanced fertilizer, such as 10-10-10. Apply fertilizer in early spring before bud break. The recommended rate is one-tenth pound of actual nitrogen per year of tree age (tree age is the number of years since the tree was planted in the home garden).

For example, a 5-year-old tree should receive 5/10 or a half-pound of nitrogen. Uniformly broadcast 5 pounds of the 10-10-10 fertilizer (10 percent of 5 is a half-pound of nitrogen) in a circular band beginning about 2 to 3 feet from the trunk and extending out slightly beyond the drip line of the tree. One pound of actual nitrogen is the maximum for fruit trees 10 years and older.

However, if the lawn in the vicinity of the fruit trees is fertilized on a regular basis, there should be no need to fertilize the trees. For more questions, call the Linn County Master Gardener Hotline at (319) 447-0647.