Sorry for intruding
Yviestevie Posts: 7,043
I don't normally post on here but I am having a real problem with blackspot this year. I have load of roses but it's not normally a problem. Is it a particularly bad year or am I just unlucky. They have been fed, well watered and mulched. I even clear away any old leaves in late winter/early spring.
Hi from Kingswinford in the West Midlands
I think wet and warm is what blackspot spores like... in fact, that's ideal conditions for a lot of fungal infections. I'd guess you've just been unlucky with the weather, if you've not been doing anything different from usual. I'm by no means a rose expert though, so perhaps @Nollie might see this and comment...
It seems to be a bad year for fungal diseases all-round this year and changeable weather has really not helped at all. So welcome to the rest of the black spot club, I am a very active member! Keeping good airflow around roses with nothing overhanging them helps and picking off the worst leaves, but tbh, once you’ve got it, it’s hard to get rid of as the spores float around..
However, I also found a report by gardendesign.com that says:
A Cornell University researcher demonstrated that a mixture developed for powdery mildew—1 tablespoon of baking soda mixed in a gallon of water, with a bit of horticultural oil or liquid soap added to help it cling to the leaves—is also effective for reducing the spread of black spot.
That will be my backup plan.
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
I don't have roses, but for the past 3 summers I've had more than my fair share of mildew on lots of plants - I thought it was because I was spray watering in the evenings, but it's not. I'm sorry I can't help, but you're not alone!