Why should I fertilize my trees and shrubs?  

Tree and shrub fertilization can stimulate growth and maintain vigor. Most soils not disturbed by construction have plenty of nutrients to help with plant growth. The factors causing most tree and shrub problems are not nutritional but heavy clay soils, poor drainage, and incorrect planting. Since most urban environments have been disturbed by construction, and the natural cycling of nutrients is disrupted by leaf removal, there is a need to add nutrients back to the soil for tree and shrub use.