How can I change my hydranger flower colours from light blue and pinkish blue to dark blue?
Reg answers:
Suitable varieties of Hydrangea can have their flower colour manipulated by altering the pH levels around the plant. Where the soil is alkaline the blooms are more pink, while under acid conditions they turn blue. What you need to do is apply a product called Hydrangea Colourant, this is widely available here in the UK under the Garowing Success and Vitax brands, but I expect there are similar products on sale in the US Otherwise make the soil more acid by adding a product containing sequestered iron, but Hydrangea colourant would be a cheaper alternative - it contains powdered alum.
I read through quite a few sites for you re white to blue. there do not seem to be a deffanite answer. They were mainly why had their plants turned from to pink. Maybe it is something in the soil.
HTH you.
