Westland Hydrangea Colourant contains a combination of iron and aluminium salts. This acidifies the soil to change pink flowers to blue. This also helps rooting and establishment of cuttings.Changes flowers from pink to blueAcidifies the soil to produce blue flowersA combination of iron and aluminium saltsCan be added to alkaline soil to change pH.Easy to useCoverage:Up to 10m²How to Use:For established shrubs - Mix the Hydrangea Colourant into the soil at the rate of 50g per square metre. Every 7 days during the growing season dissolve 50g of hydrangea colourant in 5 litres of water and apply to the area of soil covered by the shrub. Do not apply directly on plant foliage.For container-grown Hydrangeas - When potting, mix the Hydrangea Colourant into the compost at the rate of 50g per 5 litres of compost. Every 7 days during the growing season dissolve 50g of hydrangea colourant in 5 litres of water and water the soil round the plant. Best results are obtained with plants growing in a