For Jobe’s 06005 Fertilizer Spikes, the number of spikes per plant depends on the size of the plant or tree: Small plants or shrubs: 1 spike Medium-sized plants: 2–3 spikes Larger trees or shrubs: 4 or more spikes, spaced evenly around the drip line The key is to insert the spikes 2–3 inches away from the stem or trunk, and space them evenly to ensure balanced nutrient distribution. And remember—these are slow-release, so they typically last 6–8 weeks before needing replacement