The addition of Tui Hydrangea Blue to your garden will enhance the deep; blue colour of your hydrangeas. Tui Hydrangea Blue also benefits other acid-loving plants such as azaleas; rhododendrons; camellia; ericas; daphne; gardenias and kalmias; acidifying soil to create ideal conditions for healthy growth. Acidifies soil to reduce the pH level. Use in your flower garden.