Trees for Tennessee Landscapes - Maintaining and Protecting
Trees in residential and commercial landscape plantings are often fertilized to keep them healthy and attractive. Over-fertilization is common, causing excessive growth, especially on young nursery stock. Trees growing in lawn areas usually receive some nutrients when the turfgrass is fertilized. This is usually sufficient to maintain most trees in fertile soil. However, fertilization may be needed on altered soils where unconsolidated fill material has been added or the topsoil has been removed. Managed urban areas where fallen leaves are removed may also require a fertilization regime to enrich soil and replenish nutrients.
Fertilizer (plant nutrition) is no substitute for environmental factors, such as sunlight and water, which must be in balance if a tree is to develop its full potential. Trees that are healthy and growing vigorously are less susceptible to attack by insects and diseases. An application of fertilizer may, in some instances, improve the tree's resistance to further infestations of certain pests. For example, maple trees will recover from mild cases of Verticillium wilt following applications of nitrogen fertilizer.
"SP548 Fertilizing Landscape Trees," The University of Tennessee Agricultural Extension Service, SP 548-15M-11-99 R12-4910-17-002-00, http://trace.tennessee.edu/utk_agexfores/66