Can I Make A Blue Hydrangea From A Pink One?
Is there a natural way to make them blue hydrangeas instead of pink? Will white pine needles
as mulch do it? If not a natural way is there a chemical I can use to
get blue blooms?
I live in northwest Michigan in zone 4 or 5 depending on the map I use.
The plant was new last year and bloomed pink. I wasn't sure about
pruning the plant back last fall so left it about a foot tall. It
doesn't look like it made through the winter but new growth is coming
from the bottom. Does that make it a new plant again this year or is
that typical for hydrangeas? Thanks for all of your work and good info.
Sure there is a way to make them bloom blue.
You get out your paint spray can and when the blossom opens right up,
you wail away and turn 'er blue. ;-)
No? OK. Hydrangea turn blue when the soil is acidic. They produce
pinkish flowers when the soil is alkaline to neutral.
To turn blue hydrangea blue you can use an acidic fertilizer - a
chemical containing aluminum sulphate is used in that mix.
Frankly, this isn't an organic approach and there is some research that
shows aluminum is responsible for killing off root hairs on plants.
An organic approach is to use sulphur and peat moss to make an acid
soil bed and plant the hydrangea in that. Naturally, I'd suggest you
have your soil tested and then add things but most gardeners rarely do-
they just add the sulphur a little bit year by year until they get the
blue color. ;-) Your call.
Pine needles as mulch will not turn the soil acidic, neither will they
maintain an acidic soil level.
The deal is though that Hydrangea roots are going out from the plant a
long way and that you have to turn the entire bed acidic to really keep
those feeder roots doing their thing. It isn't a one time shot as the
soil will turn itself back to the surrounding acid level over time.
These Hydrangea macrophylla blue varieties bloom on old wood. So if the
buds are pruned off last year or they die due to cold, you won't have
blooms. Many cold area gardeners can grow the shrub itself but the buds
all die during the winter. If you have to prune, do so within six weeks
of blooming. Your particular plant may be alive but it won't bloom blue
if it died to the ground (heck, it won't bloom at all if it died to the
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Other Hydrangeas Don't Turn Blue
Other Hydrangea such as Hydrangea arborescens with common varieties
'Annabelle' and 'Grandiflora' can be pruned with a lawnmower and will
bloom every year. However! They do not bloom blue - but rather white
(fading to pink)
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