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).
Hydrangeas like a lot of water, and it is necessary for producing the big, beautiful blooms that are the main reason for growing hydrangeas. A drip irrigation system is a good choice for making it easy to water well and often. The color of blooms your hydrangea will produce depends a great deal on the condition of your soil. Even if you buy what's supposed to be a pink hydrangea, if your soil is acidic, you'll get blue blooms.