P LA N T IN G S
outdoors
Hydrangea queries are
popular fo r the Garden D octor
at
B H G .co m /g a rd e n q u e stio n s.
Here are answers to the most
com m on questions.
by SUSAN APPLEGET HURST
,
Q
I fell in love
with those
eavenly blue
hydrangeas, but mine
have turned a muddy
violet. Can I make
them blue again?
If you planted a hydrangea
with blue—or pink-
flowers, it is one of the
bigleaf hydrangeas
(Hydrangea macrophylla),
which depend on soil pH
to determine those hues. A
low pH (around
5
.
2
-
5
.
5
) is
an acid soil, and it brings
on the blue tones. As pH
moves up from
5.5
toward
6
, blooms turn pale blue or
violet hues. Soil pH above
6
encourages bigleaf
hydrangeas to produce
pink tones. To bring the
blue back, lower the soil
pH at planting time by
mixing the soil
50/50
with
sphagnum peat moss. After
planting, make an annual
application of aluminum
sulfate to the soil around
the plant. Follow package
directions carefully. It
may take a season or two,
but the blue blooms
should return.
118
JUNE 2009 BETTER HOMES AND GARDENS
PHOTO: WILLIAM STITES
