Buds = Flowers
If those buds are damaged by cold weather, or removed by pruning at
the wrong time of year or by deer browsing, you will have few, if
any, flowers the following summer. They are best pruned as soon as the flowers begin
to fade, because new flower buds are formed soon after they finish
flowering. Unless the plant is outgrowing its space, there really is
no need to prune bigleaf hydrangeas annually.
The best approach is
to periodically remove the largest, oldest canes at the soil level
to encourage new stems to sucker up from the base. This type of
renewal pruning will result in larger blooms without giving your
hydrangeas that sheared look. The added benefit of pruning this way
is that even if you prune at the wrong time of year, you will not be
removing all of the flowers, just those atop the stems you cut out.
'Glowing Embers' Hydrangea
You may actually get a few flowers later in the summer because some
bigleaf hydrangeas have the ability to bloom on old and new
wood. The term "bloom new wood" refers to plants that bloom on the
current season's growth. Plant breeders are exploiting this trait to
come up with new macrophylla varieties that bloom more
reliably in colder climates. A good example is the popular recent
introduction called Endless Summer®. New cultivars with this
characteristic are in the pipeline and will become available as they
prove their garden worthiness. They are understandably popular with
gardeners in colder climates. After all, who doesn't love those
long-lasting pink or blue flowers?
Other Varieties of Hydrangea
There are other varieties of hydrangeas that bloom more reliably in
our climate. These include saw-tooth hydrangeas (Hydrangea
serrata). Although they bloom on old wood, they are native to
the mountains of Japan and Korea, and are better adapted to colder
climates such as ours. Like bigleaf hydrangeas, their blue or pink
flowers can be lacecap-type or mophead-type, depending on the
cultivar. Our native smooth hydrangea (Hydrangea arborescens)
blooms on new wood, so it grows very well here.
include 'Annabelle' and 'Dardom' (White Dome®). Peegee hydrangeas (Hydrangea
paniculata) are old-fashioned favorites, frequently grown as
small trees. They bloom reliably on new wood, and the plants are
long-lived. Excellent cultivars of peegee hydrangea include 'Tardiva,'
'Pink Diamond,' and 'Bulk' (Quick Fire). Last, but far from least,
is oakleaf hydrangea (Hydrangea quercifolia). Native to the
southeastern United States, oakleaf hydrangeas also bloom on old
wood, but their flower buds are hardier. Good cultivars include the
compact 'PeeWee,' the double flowered 'Snowflake,' and 'Snow Queen.'
Now if we could just breed hydrangeas that taste awful to Bambi!
Bagworms on Arborvitae
When to Prune