Fertilization is a very important component of plant health care in the landscape. Fertilization is necessary to supplement naturally occurring essential mineral elements in the soil to maintain an optimum supply for plant growth. Soil analysis (testing), combined with observations of plant growth, are the keys for the home gardener to develop the most effective nutrition program for the landscape. The mineral elements critical for optimum growth and development of landscape plants must be present in the soil and plant at proper levels.
Maintenance programs should be developed for trees and shrubs in both residential and commercial landscapes. A good maintenance program includes monitoring and controlling insect and disease problems, suppressing weed competition, and making timely applications of water, mulch, and fertilizer.
Tree and shrub fertilization is especially important in urban and suburban areas of Virginia where soils have been altered due to construction. These urban soils tend to be heavily compacted, poorly aerated, poorly drained, and low in organic matter. Even where soils have not been affected, fertilization may be needed as part of a maintenance program to increase plant vigor or to improve root or top growth.
How and when to fertilize landscape trees and shrubs depends on:
Visual inspection of trees and shrubs is often the best overall factor to use in making fertilization decisions. Look for:
In addition to observing signs of possible nutrient deficiencies on plants, soil and foliar analysis can be used to help determine or confirm whether supplemental fertilization is needed.