Tree & Shrub Fertilizer Spikes 15-7-6 Time Release Fertilizer for Trees & Shrubs.  

• Features : "• Pre-measured so you won't overfeed or burn • Slow-release formula • Feed at the roots • No mixing or measuring >> These convenient; easy to use spikes provide a continuous supply of nutrients where your trees need it most at the roots. They require no mixing or measuring and are easy to insert around your tree's dripline. These spikes work hard so you don't have to."