Consequently, these plants are frequently forgotten or neglected in the normal lawn fertilization program. Plant signs indicating the need for fertilization include lack of terminal growth, pale green or yellow leaves, mottled leaves, dead branches, stunted leaves and early loss of leaves. Young trees should have at least 9 to 12 inches of terminal growth per year. Large mature trees usually average 6 to 9 inches of growth. Shrub vigor is the same way.
Growth varies from season to season and from variety to variety.
It also depends on the species and size being examined. Instructions for taking a soil or leaf sample can be obtained from the county Extension office. Such analyses allow the application of fertilizers in amounts and ratios that minimize nutrient waste and the threat of pollution. Without such analyses, general lawn fertilizer recommendations of 2 to 4 pounds of actual nitrogen per 1,000 square feet per year will meet the needs of most trees and shrubs. In turf areas, do not apply this amount at one time but rather make several applications to prevent fertilizer burn of the turf.