Espoma Organic Holly-Tone All-Natural Plant Food, 4-3-4 Formula, 36 lbs. This dry plant food is rich in natural organics and has been used and recommended by professionals for decades. It is specially formulated for acid-loving plants such as azaleas, camellias, dogwoods, evergreens, hollies, and rhododendrons. Holly-Tone also contains Bio-tone, Espoma's proprietary blend of beneficial microbes, which biologically enhances the organic fertilizer to ensure superior plant growth.