Some of the varieties developed from pee gee hydrangea have a large number of sterile flowers in the outer ring, while some have only these sterile flowers, and they are unable to produce seed. The variety ‘Grandifolia’ is one of these. In past decades it was among the most popular garden shrubs in Finland. Mustila’s own namesake variety (H. paniculata ‘Mustila’) closely resembles in outward appearance the natural pee gee hydrangea.
In addition to the ‘Mustila’ variety, there are also true young pee gee hydrangeas growing at the Arboretum, from natural seed collected on Hokkaida and the Kurile Islands. In recent years about 40 pee gee varieties have been planted to discover which of them are best suited to Suomi conditions. The species is a valuable addition to Finnish gardens, flowering as it does in late summer and autumn when very few other shrubs are in flower.