Jobe’s Organics Fertilizer Spikes For Outdoor Trees & Shrubs is the first spike form organic fertilizer. These all-natural organic 5-5-5 fertilizer spikes are specially made to benefit trees and shrubs. They help promote a nourishing, healthy environment that provides valuable microbial action at the roots - where trees and shrubs need it the most. This “in-ground” feeding is considered to be the most efficient delivery system for organics. The spikes will boost the soil quality long-term by promoting microbial growth. The pre-measured spikes allow for a quick, easy and no-mess application. Apply in the early spring or late fall for best results.