Help! We live in North Bend and have several Hydrangeas. I have a large Annabelle that
has never bloomed properly. Is there some special care or
fertilizing that I can do to encourage normal blooms on these
plants?
Here is some information on how to improve flowering, from the U.S. National Arboretum:
Excerpt:
“There are three possibilities for lack of flowering among the hydrangea
species. The first two too much shade and improper pruning apply to
all hydrangeas, while the other weather-related damage to flower buds applies primarily to the bigleaf hydrangea.
“While most Hydrangea species benefit from some shade, too much shade can
reduce flowering. This is particularly true of panicle hydrangea, which
is the one Hydrangea species that grows well in full sun. If you have a
hydrangea that used to bloom well but now flowers only sparsely, evaluate
whether the growth of nearby trees has reduced the amount of light that
reaches the hydrangea. If so, you may want to consider moving the
hydrangea to a sunnier location.
“Improper pruning can also reduce flowering in Hydrangea. Since bigleaf
and oakleaf hydrangeas flower on previous year’ s growth, potential
flowers buds would be removed if the plants were pruned in fall, winter
or spring. Panicle and smooth hydrangea flower on this year’s growth, so
pruning them in early summer would reduce or eliminate flowering for that
year.
“The most common reason for lack of flowering in the bigleaf hydrangea is
unfavorable weather. Most H. macrophylla cultivars flower primarily on
previous year’s growth. Weather conditions that damage aboveground parts
of the plant can reduce flowering. Damaging weather conditions include
early fall freezes that occur before the plant is completely dormant,
extremely low winter temperatures, and late spring freezes that occur
after the plant has broken dormancy. In USDA Cold Hardiness zone 6 and
warmer, which is the recommended growing area for H. macrophylla, the
most common of these unfavorable weather events is late spring freezes
that damage tender new growth. This is particularly true in the
southeastern U.S., where ‘see-saw’ temperatures are very common in the
spring.
“Bigleaf hydrangea responds quickly to warm temperatures in late winter
and early spring by breaking dormancy and producing new leaves.
Unfortunately, these spells of warm weather are often followed by periods
in which temperatures reach well below freezing. The severity of the
damage caused by these freezes depends on how many of the buds had broken
dormancy. If a substantial portion of the buds on a stem were actively
growing, the whole branch may die. For some cultivars, the loss of the
aboveground part of the plant will completely eliminate flowering the
following summer. The plant will produce new buds from the base of the
stems, but stems produced from these buds will not flower in these
cultivars.”