Organic prevention of BS on Austrian Copper and Persian Yellow
I posted this query on the roses forum and thought I'd ask here too. I've ordered two Austrian Coppers and a Persian Yellow to plant together at the top of a hill this spring. Yes, I know they're blackspot magnets. I'd be interested to know anyone's experience in doing preventive organic spraying on these two, i.e. the baking soda and/or milk treatments. One respondent told me these treatments were only for PM, not BS.
Many thanks in advance for any advice or experience you can share.