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.

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
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary

many thanks for you help

Hi Mossie, further to the very good advice, you may find the following useful. I grow hydrangeas semi- comercially and add 1 oz of lawn sand to the pot in spring to maintain the blue colour. Now lawn sand contains iron in the form of ferrous sulphate, which will give you a blue flower (depending on the variety) but as has been stated, alluminium will give the best blue and for that, if you have no alluminium sulphate, add half a dozen alluminium roofing felt tacks per pot (in the soil) which will last several seasons.
best wishes, Lannerman.

Shit in it's flowerpot