Westland Hydrangea Colourant is a salt which changes pink hydrangea varieties to blue. It also changes darker pink varieties to mauve blue. This colourant easily absorbs nutrients, as well as nitrogen for greener leaves.
When using Westland Hydrangea Colourant, obtain the best results with plants growing in acid soils. Use ericaceous compost where the soil is naturally alkaline and alternatively, double the application rate.