Hydrangea Serrata Blue Bird (Blue Bird Hydrangea) is a vigorous hydrangea which blooms from June through 'til frost. Its foliage also has lovely fall colors. You can expect this Hydrangea to reach an average size of 4’ tall by 4’ wide and it prefers to be located in rich, well-drained soil. The Blue Bird Hydrangea is tolerant of some sun. Serrata Hydrangeas in general do not require much pruning except to achieve a tighter plant or to maintain a shorter size.