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The sheervariety of hydrangeasavailable at garden centers speaks to their popularity.
Gardeners adore the billowy blooms and elegant foliage they bring to the summer garden.
But sometimes hydrangeas fail to bloom.
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You may be surprised that improper pruning commonly plays a role.
Not all hydrangeas are alike.
The group includes several species that fall into two distinctpruninggroups: old wood and new wood hydrangeas.
These flower buds overwinter on the shoots and pop fire up following spring or summer.
Other reasons plants may fail to bloom include deer browsing and late spring freezes that also damage these buds.
These Southern Belles have large shiny leaves and stunning blooms that can shift color depending on soil pH.
They fall into two main groups, mopheads and lace-caps.
Oakleaf hydrangea (H. quercifolia) is another old wood species with handsome foliage and large cone-shaped blooms.
Native to southeastern woodlands, oakleaf hydrangeas have vibrant fall color and attractive, exfoliating bark.
The best time to prune hydrangeas that flower on old wood is in summer after plants complete blooming.
In general, old wood hydrangeas require little pruning.
Simplytrim back branches to a healthy bud.
Consider cutting back stems that cross or rub against one another.
Climbing hydrangeas are vigorous growers and sometimes require a heavier hand to keep them trained to their trellis.
For all species, dead or damaged branches can be removed at any time.
Big-leaf hydrangeas can be pruned more aggressively.
Leave several stems of old productive wood as well as strong new stems that will flower next season.
The flowers open a few months later in summer.
Panicle hydrangea (H.paniculata) and smooth hydrangea (H.arborescens) are commonly grown new wood species.
Panicle hydrangeas are robust plants that thrive in the hot and humid summers of the Deep South.
Smooth hydrangeas are native to the southern US and produce massive flower heads up to a foot in diameter.
Many people mistakenly call smooth hydrangeas by the cultivar name ‘Annabelle’, an old and still popular variety.
A number of new cultivars exist, producing white, pink, or green flowerheads.
New wood hydrangeas are pruned in late winter or early spring, before new growth begins.
Because we are pruning in the dormant season, all existing stems are considered old wood.
Remove any stems that cross one another or appear dead or damaged.
Dont worry about removing flower buds through this aggressive pruning because they have not yet formed.
The primary difference between old wood and new wood hydrangeas is their flowering habits and related pruning needs.
Pruning is restricted to after plants finish flowering so as not to remove potential blooms.
They flower in mid to late summer, as these developing buds need time to mature.
New wood hydrangeas can be pruned during the dormant season without the risk of impacting flower production.
Likewise, water and light requirements vary between species.
