Make sure you have healthy, beautiful trees all season long with Ross® Root Feeder Refills for Trees & Shrubs. Use Refills in your Ross Root Feeder to get the perfect balance of nutrients directly to plants roots - while watering too. With other fertilizers, you dont know how much of the fertilizer is actually reaching your plant. The refills are a special high-nitrogen formula for deciduous trees and shrubs. These premeasured refills make for fast, easy and mess-free fertilizing.