Jobe’s Fertilizer Spikes for Trees & Shrubs ensure a continuous supply of nutrients below the surface, where the trees’ active roots are growing. Jobe’s Spikes are easy to insert around each tree’s dripline, and the slow-release formula lasts all season. No wasteful runoff, no mess, hazards or smells – only a safe beautiful yard. For best results, use Jobe’s Fertilizer Spikes for Trees & Shrubs in early spring and late fall.