Originally Posted by David E. Ross[_2_]

On 1/30/12 4:15 AM, mossie wrote:
Been a keen gardner for many years was given a lovely blue hydrangea and
would like to know how to keep it blue,also still has some faded blue
flowers on, should i cut them of now or not,it is simply not a plant i
have had in the past .
thanks in advance.

The blue results from the presence of aluminum sulfate in the soil.
Additional acidifiers can make the blue even more intense, but the
aluminum is key.

Flower remnants can last a few months. The plants may be pruned as
severely as roses. However, the timing of pruning depends on how the
plant normally blooms. If it blooms on new growth, prune while the
plant is dormant in the winter. If it blooms on old growth, prune right
after blooming.

The standard garden hydrangea (H. macrophylla) blooms on old growth.
They do poorly in areas with sub-freezing temperatures in winter. That
is because the flower buds already exist on the branches before winter
begins and are damaged during a freeze. Some other hydrangea species
are more hardy, especially those that bloom on new growth.

--
David E. Ross
Climate: California Mediterranean, see
My Climate
Gardening diary at David Ross's Garden Diary -- Current