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Black spots on roses

Gardening Reference » Gardening in 2006
by Sylorna on August 02, 2006 01:09 AM
Somehow it reminds me of a childrens song "black socks they never get dirty", only you'd replace "socks" with "spots"
sorry for the digression
So here's the low-down. I've been working at a garden center for the summer and it's been great! BUT beacuse of all of the gardening that I do there (we also have an acre of show gardens) my plants at home have suffered slightly. A couple of weeks ago I finally got around to doing some rose care and they aren't looking so hot.
They all have black spot, some worse than the others, and one has aphids. I'm told to use a mild soap solution on the aphids, no problemo. 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. Our greenhouse manager suggested a hydrogen proxide dilution, but I haven't gotten the dilution rate from her yet (if you have it could you please pass it on?). So I'm looking for suggestions on what people have found works.
by eClaire on August 02, 2006 04:14 AM
NOthing besides removing the leaves has worked for me, and my roses are not looking so good this year because of all the moisture and humidity.

I hope you find a different solution, I may try it too [Smile]


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by netty on August 02, 2006 07:23 AM
One of my roses is suffering badly from blackspot this year too. I had been spraying it with Funginex but the blackspot seems to have become resistant to it. I remove the leaves and make sure that there is no debris anywhere on the ground. I'm afraid this will spread to the other roses so I'll be watching this thread for a more natural solution.

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by Patty S on August 02, 2006 09:19 AM
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! [Frown]

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.) [dunno]

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! [grin] I've done almost the same thing to many of my large rose bushes since then, & they bounce right back as though they're thanking me!

I can't find anything specifically about the treatment of Black Spot (or for rose care) in the Garden Helper plant guides or plant profiles! (Could I be looking in the wrong places? [dunno] 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.

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