This year, at the very beginning of the
growing season, I applied systemic
rose &
flower Care granules to everything, then followed it up with a Fungicide/Insecticide/Miticide spray, weekly. For the first time ever, I had lovely
rose bushes with no Black Spot!
(But that didn't last long!) We had a "false summer" early this
spring, followed by an unusual amount of rainfall... & the Black Spot started moving in. Like Clair's
roses, that extra moisture has had mine looking awful this year... & the aphids have been holding conventions on them!
It was impossible stay on a schedule with the spray, because it would get washed off, & I couldn't find the granular form of the F/I/M treatment anywhere. (I'm just SURE I've had it before, but because the spray treatments absorb through the leaves & distribute "the medicine" throughout the
plant, I think it also lends the added benefit of a "topical" treatment, so I don't think the granules would have been as effective.)
I'm convinced that the first (& most important) part of fighting Black Spot is removing the affected leaves
...and not just getting them "off" the plants, but getting them completely out of the area, INCLUDING, as Netty said, getting them off the ground under the bushes, as it's my understanding that Black Spot IS transmitted to other plants through the soil. (I wouldn't put diseased leaves in my compost pile, & the easiest way I've found to clear the ground of all the pieces of fallen leaves is by using my shop vac.)
I read that I should remove the leaves with the spots on them, but that wouldn't leave much for the plant to grow on.
Jess, last year a friend gave me a potted Sterling Silver
rose bush
(Purple roses! ) ... but it was SOOO covered with Black Spot that I hoestly didn't even want to bring it home! I did though, & took it straight to the garage & stripped the leaves (leaving only about 5, which didn't seem to be "sick", as I was concerned too, about the
plant needing
something for photosynthesis). I also took it out of the pot & threw the pot & soil into the garbage, where it would all go to the dump! I thoroughly rinsed off the roots in the bath tub (where everything went straight to the sewer, instead of into my yard) & repotted it in clean soil.
YES, those were all pretty extreme things to do, but my thinking was that I didn't want the plant at all, if it couldn't be healthy! Well, it survived the radical treatment I gave it! It grew new leaves in no time, & is still in the pot... & has never had Black Spot since! (During the heavy rains I brought it in under the eaves, where it wouldn't have to contend with the excessive moisture.)
I guess that the point I intended to make there, was not to worry about stripping the bush almost bare!
Maybe Weezie or Jiffymouse can find something for us... the hostesses seem to be good at finding stuff in the back rooms around here!)
The only other thing I know about
rose care is that it's important to keep the branches thinned out in the center & try to keep them from crossing over each other, as good air circulation is important to the prevention of problems like mildew & Black Spot.