large fiery leaves of the oakleaf hydrangea are
the perfect complement for the fine textured
needle-like foliage of the spreading yew.
past couple of weeks one of my LinkedIn groups has been
discussing the best shrubs for fall color. In our garden
it was no contest-the oakleaf hydrangeas won this
challenge in blazing fashion.
it is trees or shrubs we look at fall color
scientifically. Words like carotenoids, pigments and
chlorophyll enter into the discussion, as does auxin,
gibberellins, other growth hormones and enzymes. It is
enough to get the heart racing!
simplify, conditions to make great fall colors boil down
to cool night temperatures and warm, sunny days.
Climatic conditions have the greatest effect on the
production of anthocyanin pigments that intensify the
red and scarlet colors. Conditions that most favor these
colors are sunny days and nighttime temperatures between
45 degrees and freezing. Even though we have had a
couple of record lows in Savannah this fall has-been
just about perfect.
chlorophyll in leaves decline in the fall, it is still
important for photosynthesis to take place. If an
abundance of cloudy weather prevents photosynthesis from
occurring, leaf color will be mediocre even if
temperatures are ideal. This also can weaken the leaf,
making it easy for a northern wind to blow it off.
night temperatures limit the movement of sugar from the
leaves. It also reduces the rate of respiration in the
leaf, so some sugars are converted to carbon dioxide.
Those retained are converted to colorful anthocyanin
pigments. So in addition to our oakleaf hydrangeas
showing great fall color so did our Chinese pistache,
Oliverís Taiwanese maple, Florida maple, and sawtooth
oakleaf hydrangea is native from the Gulf Coast as far
north as the Tennessee/Kentucky border, but donít be
disturbed. It is recommended for zones 5-9, meaning that
even parts of Michigan and Maine can relish in both the
glistening white blossoms as well as the burgundy red
grow yours select a site in partial shade. Keep in mind
that these are large shrubs reaching 6 to 8 feet in
height with an equal spread. Our oldest ones are
approaching 10 feet.
a bed for your hydrangeas and companion plants by
incorporating 3 to 4 inches of organic matter and 2
pounds of a 5-10-5 fertilizer per 100 square feet of
planting area, tilling deeply. Dig the planting hole two
to three times as wide as the rootball but no deeper.
The wide hole allows for the quickest root-expansion and
acclimation into your garden.
it comes to fall color the oakleaf hydrangea is superior
for another important trait and that is the length of
leaf retention. In other words the leaves donít just
turn red and then fall off a week later. They last and
last often persisting well into winter.
oakleaf hydrangea screams to be planted in a woodland
border where it can be combined with ferns, hostas, and
colorful French or mophead type hydrangeas. In the south
they should be combined with late blooming azaleas like
those from the Satsuki group which bloom in May. When
choosing fall companions however, this takes a little
favorite combination planting in our garden features the
large colorful burgundy leaves with the fine textured
needle-like foliage of the spreading yew. This is
terrific complementary partnership playing off the
contrast both in texture and color.
will be several oakleaf hydrangea varieties at your
garden center next spring. Snow Queen may be the most
famous for its upright habit and large blooms that hold
up well after rain. Look also for the US National
Arboretum released Ruby Slippers that is somewhat
shorter and more compact. The flowers start off white,
age to pink and finish to a deep rose. Its fall leaf
color is considered to be superior.
color is something most often relegated to tree
selection but shrubs like the native oakleaf hydrangea
can add their own fiery blast as well.