PeeGee Hydrangea (Hydrangea paniculata) is a beloved old-fashioned shrub that bears beautiful panicles of white flowers from midsummer to September. It requires pruning to maintain any preferred size, for if unrestrained it can grow as tall as 25 feet with a 16-foot spread. A deciduous plant, it comes in several varieties. This one, 'Tardiva', is especially appealing for its longer, more open flower clusters.