Johnsons's Garden Centers Text File document - copyright 2002
PDF file available at http://www.johnsonsgarden.com/newsletter/nurseryplants.html

How "Wood" You Prune Hydrangeas?
October 2002
Alisa DePontier, Johnson's East Store

    One of the most frequently asked questions about hydrangeas is, "Why
doesn't mine bloom?" The two most common reasons are incorrect pruning
techniques and winter kill (or late spring freezes). With hydrangeas, it
is often said that no pruning is better than incorrect pruning. This is
because there are different types of hydrangeas which require different
pruning methods.

    Use PRUNING METHOD ONE if you have Hydrangea macrophylla or mophead
(these are the most common hydrangeas grown) or Hydrangea serrata which
is also called lacecap. This is also the method to use if you are unsure
as to which variety you have.

    Use PRUNING METHOD TWO if you have Hydrangea paniculata, also known
as 'PeeGee' or Hydrangea arborescens which is sometimes referred to as
'Annabelle.

    PRUNING METHOD ONE--The first method is for hydrangeas that bloom
on "old wood." Stems are considered "old wood" if they have been on the
hydrangea for at least 9-10 months before the hydrangea blooms. This 
means that flower buds are formed on the stems of hydrangeas around
August, September or October for the following year. If those stems are
pruned in the fall or winter, the flower buds for the spring will be
removed and there will be little or no bloom next year.

    Occasionally a macrophylla or serrata will defy this general rule
and bloom after being pruned at the wrong time. But, for the vast
majority of hydrangeas, pruning after about August/September will
eliminate the bloom for the next spring.

    Pruning for macrophylla and serrata merely consists of dead-
heading or the removal of spent blooms. Cut the spent blooms, along with
the flowering stalk (or flower stem), back to the uppermost pair of new
buds. Be careful not to damage any of the new green shoots.

    In our area, where heavy freezing is likely, and more often than not
we have a late spring frost, a little winter protection is advised.
Hilling up mulch or shredded leaves around the plant will diminish
die-back and help ensure another season of breath-taking blooms.

    PRUNING METHOD TWO--The second method is for hydrangea types that
bloom on "new wood" or current year's growth. In the spring, when there
is no danger of frost damage, annual pruning may be cut back to ground
level.

    Though versatile and varied, hydrangeas are among the easiest
ornamentals to grow. They prefer a humus-rich soil, ample moisture and
relief from midday sun. Add an annual pruning--specific to the
species--and the needs of these deciduous garden favorites are fairly
well met.