Root. In the computer world, root refers to the top-level directory of a file system. The word is derived from a tree root, since it represents the starting point of a hierarchical tree structure.
Use a fertilizer with high levels of phosphorus. Phosphorus helps to prevent aluminum from creeping into the system of the hydrangea. Choose a fertilizer close to the ratio of 25/10/10 (Phosphorus is the middle number).
Maintain consistent soil moisture; mulch to help preserve it and keep soil temperatures down. Apply a hydrangea fertilizer that encourages soil acidity. Liquid seaweed and molasses sprays can help ward off fungal problems. You also can fertilize leaves and soil with diluted fish emulsion.