Blue hydrangeas need acidic soil in order to convert aluminum compounds into a form that can be used by the shrub to make the flowers blue. If you don’t have acidic soil with a pH level ranging from 5 to 7, the flowers will likely be pink or lavender.
Fortunately, there’s an easy fix: aluminum sulfate. Dave Epstein of Gardening Wisdom has some helpful tips on how to use it. But before you race to amend the soil with it, check the pH level with a home soil testing kit. If you apply too much of the amendment, you could damage the plant.
And make sure your hydrangea is a type that’s supposed to produce blue flowers. White and cream hydrangeas like Annabelle and oakleaf varieties won’t turn blue no matter what you do!
Watch the video and learn how to help hydrangeas turn blue!