From David56802@21:1/5 to All on Fri Oct 23 16:42:22 2020
Last year I used hydrangea colourant to turn my deep pink mophead
hydrangea blue. I diluted it in accordance with the instructions and
applied it once a week from early May to early July. To my
disappointment the flowers turned out mauve-purple rather than blue.
I tried again this year in the belief it would take another season to
make the soil acidic. But this summer the flowers were actually pinker
than last year!
Where did I go wrong? The only thing I can think of is that I didn't
fork around the roots before applying the colourant.