Learn How to Turn Hydrangea Flowers Blue

February 11, 2026

Early spring is the time to turn Hydrangea flowers blue! Bay Area soils are normally alkaline, which produces pink flowers. To turn Hydrangea blue/purple they’ll need to grow in more acidic soil.

We recommend using either Espoma Soil Acidifier or Greenall True Blue; both are easy to use. Time is of the essence though…because once Hydrangeas start growing from their winter dormancy, it’s too late. And with sunny late winter days, the clock is definitely ticking!