Posted: Yesterday at 13:00
Blackspot and roses are a bit like strawberries and cream, but not as nice.
The blackspot spores remain in the leaves after they're fallen to the ground at the end of the season. If you don't remove the leaves (burn them or put in the rubbish, don't compost them), then the spores are ready and waiting for the new leaves to appear next year.
If you can get rid of all the infected leaves at the end of the season and dispose of them then you may have better luck. But it is still likely you'll get some BS. Even if you plant afresh, it'll still likely affect your new bushes in a year, it's a case of damage limitation. The spores are in the air and just take advantage of any weakness on your plants.
Give the bushes a good mulch with rotted compost in autumn or spring (or both). Keep the plants strong and healthy and they can resist the disease much better.
The Roseclear warning just indicates that the product should not be used more than 4x per year. Which is likely to be for environmental reasons.
P.S nut is not a big fan of roses
Last edited: 26 July 2017 13:01:31