Fall leaves shredded with the mower, grass clippings left on the lawn and fertilizer applied to other plants provide most of the nutrients your trees require. But occasionally you may need to give your trees a nutrient boost.
Late fall after leaf drop or early spring before growth begins are the best times to fertilize. Consider using a low nitrogen slow release fertilizer.
Start by measuring the tree’s diameter at breast height – that’s about 4 ½ feet high. You’ll need about 5 pounds of a low nitrogen fertilizer for every inch of trunk.
Apply the fertilizer in concentric circles, starting 2 feet from the trunk, throughout the tree canopy and several feet beyond. Remove small cores of soil or use a dandelion digger to place a portion of the fertilizer in small holes about 2 feet apart and at least 6 inches deep - just below the grass roots.
A bit more information: Wait at least a season after planting to apply fertilizer to trees and shrubs. New plantings are under stress and should only receive a light fertilization. Make a light application of a low nitrogen slow release fertilizer around the perimeter of the planting hole.