Analysis: 16-4-4. It is no secret that beautiful, healthy trees make your yard look spectacular. Jobe's Fertilizer Spikes for Trees & Shrubs ensure a continuous supply of nutrients below the surface, where the tree s active roots are growing. Jobe's Spikes are easy to insert around the tree s dripline, and the slow-release formula lasts all season. No wasteful runoff, no mess, hazards or smells only a safe beautiful yard. Spikes are specially formulated for all deciduous trees and shrubs. For best results, use Jobe's Fertilizer Spikes for Trees & Shrubs in early spring and late fall.