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Black spots on roses- cut all leaves? :(

Posted by vitoro NC (My Page) on
Wed, May 12, 10 at 17:45

So, I found out I had black spot on my roses awhile back and had bought a spray for it and aphids. I started using that and clipping the leaves that had spots in an attempt to avoid it spreading. WELL, that didn't really work because all the leaves have black spots on them, and now I'm curious.. should I consider my rose as good as gone? Do I cut off all the remaining leaves? Do I cut down the... stems or whatever.. canes I think they're called? WHat do I do now? Basically if I remove the black spotted leaves, my plant will be bald. I mean, I seriously have no clue what I should do now :( Please help!


Follow-Up Postings:

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RE: Black spots on roses- cut all leaves? :(

The key to blackspot is prevention. Once the leaves have bs on them, they will fall off. You can prevent the leaves that don't have it yet by spraying with Bayer Advanced Disease Control. I'm not sure what spray you used.

What you need to do is get the Bayer or another good spray and use it once a week until the bs is under control. Then you will spray every other week. The roses will put out new leaves and be fine. The diseased leaves will drop off. You can prune back if you want to, but you don't have to.


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RE: Black spots on roses- cut all leaves? :(

Will Neem work against black spot? It's labeled as a fungicide...

Thank you.


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RE: Black spots on roses- cut all leaves? :(

It won't cure or stop existing black spot.And if vitoro's roses all have it so bad they are defoliating, I doubt neem would do much to prevent it. He's better off with Daconil for prevention and the Bayer now to stop the current spores.


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RE: Black spots on roses- cut all leaves? :(

Pirula, the short answer is, in VA- No.
It can burn the rose leaves when the weather is hot, but does very littly for control of BS in areas where this is a serious issue. The best approach here (I am in MD close to VA border) is to plant resistant varieties, if you don't want to spray Bayer or Banner or any other serious fungicide.
I believe I tried in the past every possible available orgnic solution (sulfur, copper fungicides, baking soda formula, milk, wilt pruf, rosa flora, neem oil, compost tea, seranada, fish emulsion, kelp, etc.) The best was sulfur, I used it for 6+ years and it worked reasonably well on resistant roses which need just a little help, but roses succeptable to BS will get BS with sulfur spray anyway. It also can burn leaves if the temps are high.
Now I try to change to completely no spray garden, but not quite there yet.
Olga


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RE: Black spots on roses- cut all leaves? :(

You do not need to cut the leaves--they will eventually fall off on their own. Blackspot is rarely fatal. It does weaken the plant, however, and certainly makes them ugly. A regular spray program will help, but a careful selection of resistant roses is really your best defense. Don't be discouraged. Everyone east of the Mississippi struggles with it. Some years are worse than others.


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RE: Black spots on roses- cut all leaves? :(

It is indeed rarely fatal, but if you have a severe winter following a bad blackspot infection on your roses, the weakened state of the roses (caused by all the leaf drop) going into the winter may contribute to extra winterkill.

That may well not be a problem for you in North Carolina, but it can be a consideration in the Philadelphia & Boston regions.


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RE: Black spots on roses- cut all leaves? :(

I started using Garden Safe Fungicide as soon as I knew about the black spot and was spraying it on once a week. Problem is that ALL the leaves got black spot anyway, so I guess it's not so effective, or my plant was doomed from the beginning. It's just sad because everyone else's roses look amazing on my street, and I have the one scraggly branched leaf-less one on the block... I'm almost thinking cutting it back MIGHT be best, if the plant is really so weak. There are absolutely NO new leaf growths whatsoever. And only 3 (yes 3) spot free leaves.


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RE: Black spots on roses- cut all leaves? :(

It is hard to justify spraying just one rose these days, when there are so many disease resistant roses out there these days. The people who develop new roses have made quite an effort to turn out disease resistant varieties--so you have a lot more choices than when I got started in 2001. At the last club auction I attended we pointed the disease resistant varieties--these went for the highest prices.


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RE: Black spots on roses- cut all leaves? :(

What rose is it? Is it only one rose that you have or only one that has black spot?


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RE: Black spots on roses- cut all leaves? :(

  • Posted by jim1961 z 5/6 central pa (My Page) on
    Thu, May 13, 10 at 9:11

Garden safe fungicide looks to be a 3-1 spraying product with extracts of neem oil. I can see why this product would NOT be effective in your area.
You may want to think about replacing it with a more Blackspot (disease) resistant, more vigorous growing rose.
But, that's up to you! Best of luck and I hope things work out for you whatever you decide to do!


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RE: Black spots on roses- cut all leaves? :(

It's just the one rose bush- err.. sticks :(.. ha.

I have a double knockout on the other side of my house which is doing just fine and disease free, and I have absolutely no idea what variety of rose the one that has black spot is. To my novice eyes, it's a run of the mill red rose? At this point I'm just going to watch it and see if it improves and look into a better treatment..


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RE: Black spots on roses- cut all leaves? :(

I have also found that sometimes spotted leaves do not fall off. they get spots but they dont always fall off. Atleast not for a while. I had some develop last year when I missed a two weeks period of spraying but the pants didnt die and this year they are looking fantastic as I now mark down my spray dates on the calender and keep track better than I used to.


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RE: Black spots on roses- cut all leaves? :(

Yes, that was my question. What if it looks like black spot, but the leaves don't fall off? Maybe what my roses have isn't black spot after all. Based on my researching today though, if it isn't black spot, it must be a nutrient deficiency (which is very possible). Does anyone know if there are nutrient deficiencies that look like black spot? The closest I've seen so far is potassium deficiency.


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RE: Black spots on roses- cut all leaves? :(

If there are black spots, it is probably "blackspot"--LOL!

The best fungicide for blackspot is Bayer Advanced Garden Disease Control for Roses, Flowers, and Shrubs. However, it comes only in larger quantities--which would be a bit much for one rose.

What you can do is check at Wal-mart, Home Depot, and such places for a pre-mixed bottle of Daconil (kinda like a 409 bottle, but in bright red) and use it on your one problem rose. Kinda an expensive way to spray regularly for blackspot, but for one rose, it would take you a number of years to use up the Bayer Garden Disease Control--so its a six one way, half dozen the other way kind of situation.

Good luck,

Kate


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RE: Black spots on roses- cut all leaves? :(

At least a third of the leaves on my Easy Living shrubs had fallen to black spot in July. I watered deeply, sprayed with fish emulsion, went to the beach for a week. When I got home, all three shrubs had bright clean leaves, by the next week, they were covered with buds.


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RE: Black spots on roses- cut all leaves? :(

vitaro, since it is only one rose I'd recommend that you pull off most (not all) of the leaves. When I have done that it sped up the process since the sooner they are off the quicker new healthy leaves come. I am in a heavy black spot area and I have never found the more organic sprays to be effective here. Sometimes you need to pull out the big guns. Or you can simply replace it with a rose that is disease resistant.


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RE: Black spots on roses- cut all leaves? :(

For one rose I suggest using an antitranspirant. (It is my understanding that at least one of the "big guns" is not legal in New York).


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RE: Black spots on roses- cut all leaves?

To all the blackspot sufferers, I feel your pain. For what seems to be no reason at all, my Hybrid Tea rose bed came down with the worst case of blackspot I've ever seen.

Finally switched to Bayer Disease Control for Roses, etc. after I realized realized Ortho Rose Pride wasn't doing anything and Daconil wasn't much better but very expensive.

For some reason, the Bayer products seem to do a better job for me. Also using Bayer's Merit as a drench on an ash tree-ash tree borer is a BIG problem here-and after three years, so far, so good.

Here's a question: Planted a Cornelian Cherry Dogwood this Spring about 30 feet away from the rose bed. Could it possibly be a host for the blackspot. I have started spraying it as well as it also has a fungus attacking.

Just wondering...

MM


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RE: Black spots on roses- cut all leaves? :(

Rotation of fungicide families is always a good idea to prevent development of resistance.

Here is a link that might be useful: Garden Musings


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RE: Black spots on roses- cut all leaves? :(

  • Posted by jim1961 z 5/6 central pa (My Page) on
    Tue, Aug 24, 10 at 20:22

marymarie2007,

Dogwoods do not get Blackspot marymarie2007. Dogwoods are prone to dogwood anthracnose, which blights the leaves with brown spots and makes them shrivel up.
Your Dogwood has nothing to do with your roses getting blackspot.


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