[Trillium]

My recipe with the baking soda is a cure, while I suspect that Frazzy's is a preventative. However, unless you're spraying the stuff on regularly, it's hard to keep up with blackspot in a rainy climate. Geofff Hamilton suggested overhead shelter against certain fungi, but that might be difficult on a large area and in practicality.

[Bobby T]

MJ      No    Just Rose Hip Syrup         Bob

[jackiestagg]

last summer I bought a new product called Biomagic Soft Guard, which claims to immunise plants against fungi. We get blackspot terrible here in the wet west. You really need to use it from the start of the season for best effect I suspect, but it did definitely reduce the blacspot I already had. This year I'm also going to try it on clematis against wilt. It's 'organic' although not certified (don't know why) and made by Travena www.travena.co.uk. For the technically minded among you. it contains chitosan oligosaccharin.