Hydrandea Black Steel white ball
I would very much like some advice.
I have a Hydrangea Black Steel White ball which is developing Blight pink spots on the petals. Is it supposed to be in Ericaceous compost? There were planting specifications with it an I could find nothing online, so assumed alkaline would be ok - and used 'Homebase multi-purpouse compost with 6 weeks feed'. I bought the plant for its lovely white blooms and would like to have it remain white. Someone suggested giving it a cup of white tea! Would this be a good thing to do?
Thank you in advance.