Pruning Hydrangea
Some hydrangeas bloom on "old wood" while others bloom on "new wood." So it is
important to know the variety that you have. Hydrangeas bearing flowers on woody
stems produced the previous year describes blooms on old wood. Flower buds forming on
this year's current growth appear on new wood. Shrubs blooming on old wood must be
pruned shortly after current flower so as not to remove developing flower buds. If a shrub
blooms on new wood, prune late winter or in spring stimulating new growth for additional
blooms.
General maintenance on Bigleaf and Oakleaf hydrangeas is recommended annually.
Remove all dead wood and cut about 1/3 of the older stems to the ground. This improves
plant vigor, overall shape and bloom volume. Remember to prune these two species; soon
after flowering. Bigleaf and Oakleaf bloom on old wood. There are a few Bigleaf
hydrangeas that bloom on both old and new wood. These should be chosen if you are in
an area prone to late frosts.
Smooth Hydrangea can be cut at six to twelve inches from the ground, or at half its
height, every year in late winter or early spring. Height to prune is strictly personal
preference. Pruning after initial flowering can even stimulate a second flower period.
Panicle Hydrangea is most effective in tree form. Remove lower suckers and up to 1/2 of
older stems for greater flowering. Both Smooth and Panicle Hydrangeas bloom on new
wood.
