It is the leaf of the plants, and not the actual age, which matters. Blueberry plants may be anywhere from a few months to two years old when you purchase them. However, the actual time that the plants have taken to get established in an area is far more important for cultural considerations than the age of the plants. In other words, which leaf the plant is in, is more important than chronological age. Replenish this each fall after the first killing frost.
Irrigation is necessary for good plant establishment and survival.
A drip irrigation system is recommended. Fifty-five to 110 gallons of water per 100 feet of row are required each week for blueberry establishment. These requirements may be even higher under windy conditions. If the root systems are allowed to dry out, the peat around the roots will not re-wet easily, therefore, the plants could die before water becomes available to them again. This amount is equivalent to 2.6 inches of precipitation per day.