Hydrangeas are naturally pink, but where the soil contains iron or aluminium salts, they will produce blue flowers.
If you want blue flowers and your soil isn't rich in the necessary salts, the Vitax Hydrangea Colourant for sale in Colchester, Essex, at Poplar Nurseries provides the solution.
Pale-pink varieties tend to turn blue best, with the darker pink varieties tending to produce mauve/blue flowers.
