Answer: The plants of Japanese origin are known scientifically as Hydrangea paniculata 'Grandiflora' while the North American type is Hydrangea arborescens 'Grandiflora'. The common name Pee Gee or P.G. (depending on the reference) is the hardiest of the Japanese cultivars. They bloom on new wood.
This means the twigs that emerge from near or below the ground this spring will create their own flower buds this summer and will bloom every summer regardless of the weird winter or spring conditions. This is important to know when pruning, as some hydrangeas bloom on new shoots which develop on the previous summer's wood. Since your Pee Gee will bloom on new wood, you can cut the shrub down to the ground this winter to renew it.
Pee Gees are late summer flowering plants with very narrow oval green leaves. In milder climates they reach heights of 5 to 8 feet tall, but we usually see them at about four feet tall and wide.
Like the other hardy hydrangeas, Pee Gees are treated as a sub-shrub because they are woody like a shrub but they often die to the ground and come back from the roots like a perennial plant. The flowers are clustered in conical clumps which are also described as pyramidal in form, making them distinctly different from all other hydrangeas.
Pee Gee flowers open as a pale greenish white color in early to mid-August. If we get an extended 'Indian Summer' with warm days and cool nights, the flowers will gradually turn pink, providing interesting color until October some years.
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