Jobe's® 15 Pack 16-4-4 Tree & Shrub Spike Value Pack. It feeds at roots and provides a slow release, continuous supply of nutrients to feed all season. No mixing or measuring is required. It is specially formulated for all deciduous trees and shrubs. Easy to insert around each tree's dripline, these spikes ensure a safe and beautiful yard without wasteful runoff, mess, hazards, or smells. For best results, use Jobe's Fertilizer Spikes for Trees & Shrubs in early spring and late fall.