Hydrangeas of all Kinds
Garden Clippings for August 24, 2019
The later the flower the longer the flower. While early spring flowering shrubs such as Magnolia, Forsythia, Weigela and Snowball can often be placed in the ten-day-wonder category, Hydrangeas will strut their stuff all summer long.
Hydrangeas are the mainstay of the summer garden. Most varieties begin flowering in the middle of July and will remain showy until the end of August and into September. The most common flower colour is white, followed by shades of pink, red and blue.
Hydrangeas owe their showiness to their large flowers which are mostly globe shaped and can range from 3 – 8 inches in diameter. Even if flowers are not abundant, their sheer size will bring on an impressive display.
The variety list of Hydrangeas is almost endless, with plant breeders on a continuous quest to find even better performers.
Hydrangeas can be put into 6 categories, each with their own characteristics. And although Hydrangeas grow happily without pruning, each of the 6 categories has its own pruning instructions.
Smooth Hydrangeas (arborescens) are most like the old-fashioned Annabelle Hydrangeas that were grown as hedges at Grandma’s farm garden. Since they bloom on this year’s growth, they should be pruned in early spring. The popular ‘Incrediball’ Hydrangeas fall in this group.
Bigleaf Hydrangeas have large leathery leaves and are the type you would find at the grocery store and florist shop in early spring. Although not as hardy as other Hydrangeas, they will nicely survive winters in SW Ontario. Bigleaf Hydrangeas flower in early summer on old wood, so they are best left alone without pruning. If you want to prune, do so immediately after flowering.
Panicle (paniculata), also known as PeeGee Hydrangea is identified by its cone shaped flowers. The wildly popular ‘Pinky Winky’ Hydranea is part of this group, as well as ‘Zinfin Doll’ and the dwarf ‘Bobo’, growing only 3 feet high. Panicle Hydrangeas are often grown as standards or small trees.
Mountain hydrangeas are similar to Bigleaf Hydrangeas but with interesting flatter flowers that are both complete and incomplete. Mountain Hydrangeas bloom on old previous year’s wood and probably don’t need pruning. If the plant becomes too woody, go ahead and prune it after it has flowered.
Climbing Hydrangea (petiolaris) is easily distinguished by its rambling growth habit. This vine is grown for its lush green leaves, while the white flowers are a bonus. It blooms on old wood and if you prune it in summer, you will likely forfeit flowers the following spring.
Oakleaf Hydrangea (quercifolia), like Climbing hydrangea is grown for its impressive leaves, while flowers are less abundant than its cousins. This specimen shrub is noted for its smallish size of no more than a metre high and leaves that turn bronze in fall. Leaves often remain on the plant until Christmas.
Next week we will explore how to get the most performance out of Hydrangeas.