Hydrangeas turning color?
Question: Several hortensia hydrangeas planted in a border next my lawn were a beautiful dark blue color years ago but are gradually losing their blue color and turning pink. Is there anything I can do at this time of year to help restore the color in next year’s blooms? – Jeff, Ohio Answer: The gradual change of color of the hydrangea flower from blue to pink is likely due to a change of pH or acidity of the soil. The soil is becoming more alkaline. A pH 4.5 to 5.0 is ideal for the development of a rich, blue color in hortensia hydrangea. The closer the pH is to neutral, 7.0, the more pink the hydrangea flower. If you are applying lime to your lawn, it may be leaching into the root zone of the hydrangea, raising the soil pH. To acidify the soil and restore the blue color, this fall and again next spring, apply aluminum sulfate at the rate of 1/4 ounce to a gallon of water.
