Q.Color Of My Delphinium Changed Color This Year From Blue To White.
I have 3 delphinium plants that I have had 6 to 7 years, they have always been blue.This year they are all white. I put coffee grounds around the ground in the spring to keep an acid soil.
Certified GKH Gardening Expert
Used coffee grounds will not affect your soil pH, but they do improve the soil structure. The color of flowers can be impacted by the environment, such as cold weather, drought, insects, and soil pH. (Incidentally, it appears delphiniums don't care for acidic soil, so there is no need to try to change it to acidic.)