Posted: 05/09/2016 at 21:56
Having trouble with what looks like white mildew on 4 delphiniums this summer. The well established plants were covered in it last summer so when the fresh leaves appeared this summer I sprayed them with fungus killer. However, the mildew appeared again later, even the stems of the flowers caught it.
One of my delphiniums 30ft away from the others also caught it again this year.
Should I dig them all out and start again next year. Could the disease be in the soil or do weather conditions cause the problem? Is it airborne? I garden on light sandy soil which does have a thin layer of compost put on every autumn.
Any good advice greatly appreciated.