As a result of several soil tests I have discovered that the soil around many of my hydrangeas has become rather alkaline. Also, the colors have become wimpy on many of the plants. From reading several books I have decided to add sulphur to make it more acid-----------and then aluminum for color. Does anyone have any other suggestions------------and when should these applications be done? I live in Zone 7b (where it was 20 degrees this morning but going up to 50 today).
Shirleyd
Zone 7b
Fertilizing and changing color
I'd hold off on the aluminum unless these are planted in pots. Your garden soil most likely has aluminum in it already which means all you need to do is drop the pH and you'll get your blue flowers. And too much aluminum is bad for plants, so I wouldn't add it unless you know for sure there's no aluminum in the soil. As far as when to do the amendments I'll let someone else advise you...to me constantly amending my soil to make things acidic when they want to be alkaline is not worth the effort, so I've learned to enjoy pink hydrangeas and don't bother with the amendments!
ecrane3------thanks for advice
Shirleyd