If you are looking to change your pink hydrangeas blue, then Hydrangea Colourant is ideal.Hydrangeas that grow where iron or aluminium salts are present tend to change colour and produce blue flowers. Depending on the variety, pale pink hydrangeas will turn blue best with darker pink varieties turning to mauve or blue.Best results are obtained with plants growing in acid soil, but if your soil is alkaline the proportions should be doubled.- Used for both pot grown hydrangeas and those grown outdoors- Readily dissolved in a little hot water- Mixed with soil for best resultsFor both potted hydrangeas and those grown outside, simply mix Hydrangea Colourant with the soil in which the root system will develop.After establishment, dilute the Hydrangea Colourant as directed and water weekly during growth.When to Use: March – September.Always keep out of reach of children and wear protective gloves and eye protection where possible during use.