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).
Water the hydrangea to a depth of 4 inches after cutting it back. Feed it with a 5-10-5 ratio fertilizer once the soil warms to 68 degrees Fahrenheit in spring. Avoid early feeding since the shrub will produce weak, spindly growth.