Espoma Organic Holly-Tone for Evergreen and Azalea Plant Food 4-3-4 Fertilizer 8 lb. for acid-loving plants such as hollies azaleas camellias evergreens and hydrangeas. Also is excellent for dogwoods blueberries strawberries and rhododendrons. It is rich in natural organics and enhanced with bio-tone microbes. Used and recommended by professionals. Holly-Tone s all natural formula contains bio-tone our proprietary blend of beneficial microbes. Bio-tone biologically enhances our natural plant food to ensure superior plant growth.