Jack’s Classic Hydrangea Blue Fertilizer contains micronutrients and aluminum sulphate. Enhances blue flowers like Lacecap including The Tuff Stuff series, the Endless Summer series and The Cityline series. The unique combination of high-quality nutrients as well as acidifying ingredients needed to produce a lush-leafed blue flowering hydrangea. This combined formulation of nutrients and acidic elements, along with the important addition of aluminum sulphate, will help your plants produce blue flowers.