Jobe’s Tree & Shrub Fertilizer Plant Food Spikes 15 Spike for Trees and Shrubs Summary Pre-measured fertilizer spikes nourishes at the roots; Time release fertilizer for all trees and shrubs Easy to use fertilizer spikes; No wasteful runoff, no mess, hazards or smells; Apply early spring and late fall Continuous supply of nutrients below the surface, where the active roots are growing Jobe’s tree spikes are easy to insert around each tree’s dripline, and the slow-release formula feeds all season Product Description Jobe’s Tree Fertilizer Spikes 16-4-4 Fertilizer spikes feed trees at the roots, where they need it most. Active Ingredients: Nitrogen, Phosphate, Potash, Calcium, Magnesium, Sulfur