my penstamons have got a powdery mildew. I RHS-d it and it seems some of the best known fungicides are being withdrawn from sale at the end of the year, so I'm not using them. However it's beyond gentle remedies - really taken hold in the last few weeks and I've been wondering what it is (like an idiot).
I've just ordered one on amazon and will check the local garden centre (but AFAIK they only stock the nasty one).
I love penstamon and I love bees. We have a lot of bumble bees in our communal garden. Also a lot of penstamons, as they are slug proof (world record slug population....). The worst affected plant is 4 years old and has produced a lot of flowers already but they are all 'dusty' with mildew. Any ideas please? Got to be communal garden friendly and work! thanks.