Fertilization
Fertilization is another important aspect of mature tree care. Trees require certain nutrients (essential elements) to function and grow. Urban landscape trees are often growing in soils that do not contain sufficient available nutrients for satisfactory growth and development. In these situations it may be necessary to fertilize to improve vigor.
Fertilizing a tree can increase growth, reduce susceptibility to certain diseases and pests, and can even help reverse declining health. However, if fertilizer is not applied wisely, it may not benefit the tree at all, and may even adversely affect the tree. Mature trees making satisfactory growth may not require fertilization. When considering supplemental fertilizer, it is important to know what nutrients are needed, and when and how it should be applied.
Soil conditions, especially pH and organic matter content, vary greatly making the proper selection and use of fertilizer a somewhat complex process. It is worth the time and investment to have a Certified Arborist test or soil. With the results in hand, you can then ask for advice on application rates, timing and the best blend of fertilizer for each of your trees and shrubs.