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boman47k 06-28-2010 08:04 PM

knock out roses and fungus
Needing something that can grow in direct sunlight, I looked at some knock out roses today. They had black spots on them. When I asked about the black spots, the lady said she didn't know what they were!:whistling2: When I mentioned the possibilty of fugus, she seemed to agree, but told me the black spots would normally go away when planted in the ground and new growth startes. From a little reading I have done, this does not seem likely if it is a fungus. They had hundreds in different sized pots right next to each other. I was leery of buying these plants and trying to grow them in that condition. Is it likely the spots will go away if they are transplanted and have better air circulation? I live in nw Alabama.

Any thoughts on these roses and the black spots? Would you guys chance them?

downunder 06-29-2010 04:23 PM

If Knockouts have blackspot, something is wrong. They just don't get it hardly at all. I have grown them for several years and my opinion of them is to give them 6 x 6 ft of room, plant them, and get out of the way! If you want foolproof roses, Knockouts are what you want.

However, if you want roses, Knockouts are not for cutting, fragrance, etc. They are an excellent landscaping plant used as a flowering shrub, but not my choice if I wanted a rose garden.


but told me the black spots would normally go away when planted in the ground
I've just gotta do this- Yeah, they'll go away when they drop off.

This is not the nursery you want to go to for plant purchases and advice. That staff person obviously does not know anything about roses and I really expect that you will be disappointed. As a rule of thumb, roses and blackspot go hand in hand. This has been the bain or growing roses since they began I imagine. Any person who cannot tell you about blackspot has no business selling roses- or even standing close to them IMO!

So much for my soapbox. I can understand that the plants may be stocked close together. Space is $$$ and one would expect that they don't stay there very long. If I saw them crammed together, even though they had a little blackspot I would buy them at a good price.

I almost forgot- Funginex has been used for this about as long as aspirin for headaches. Or a copper based spray. Or baking soda solution if you don't object to the white powdery residue it leaves.

If you have the room mentioned above and plenty of sun, for consistent, reliable season long color, you can't beat the Knockouts.

boman47k 06-29-2010 05:50 PM

I appreciate the reply, but I am a little confused. If the leaves are going to fall off, why buy at any price? Are you saying I can treat them and not lose them? I wanted to wait and check with someone here on the forum before I bought any.

If this is black spot fungus, they have a lot of them! I wouldn't be scared to bet there are close to 1000. But, it is what came to my mine when I saw them.

I'm only talking about 3 or 4 plants for a little decdoration for the front yard.

downunder 06-29-2010 06:45 PM

Once the leaves are affected with blackspot, they will turn yellow and fall off. But roses are vigorous growers. They will grow new branches and leaves as the season progresses. Sorry, didn't mean to get ahead of you.

Blackspot looks like someone took a fountain pen or paint gun or something like that and just sprayed the leaves. It is caused by a virus from the soil that gets on the leaves when they are wet, starting with the lower leaves. It then leapfrogs up the plant to the other leaves. Keeping a good mulch over the soil is one way to prevent or reduce blackspot. Another way is to keep the leaves as dry as possible. Always water just at the soil and not from overhead. Treat weekly with a fungicide. Learn to live with a certain amount of it. However, as I mentioned earlier, the Knockouts were bred specifically with this problem in mind and that is their main selling point for folks who want "troublefree" roses, or as close as that is possible.

On the other hand, this may not be blackspot at all.

boman47k 06-29-2010 09:34 PM


On the other hand, this may not be blackspot at all.
Well they are placed as close together as they can be, and from what I saw, they are watered from above with a sprinkler hose. Some, of course, are not as spotted as others. Mold/mildew?

So, black spot should not kill them, right? My tomatoes do not fare very well. I have seen the leaves turn yellow. I pull them off.

I do understand what you are saying about roses being robust growers and these being grown with black spot in mind. That is why I ask about the black spot killing them.

I hate to be so weird about these, but my wife is wanting some of them. Very small amount of money, but I do not like to throw money in the air and run out from under it.

downunder 06-30-2010 05:18 PM

In the sense of "Never say never," I wouldn't say that blackspot wouldn't kill a rose bush, but it would be very unlikely. It would have to rapidly and completely defoliate the bush before it could recover and put on new leaves. Basically, think about the purpose of leaves on any plant and what would happen if it suddenly and completely lost all its leaves during the growing season. Bad for any plant- rose or whatever. So with that caveat, I will say that no, blackspot will not kill the roses.

If they are at a good price- less than $10 for a 1 gallon size around here- I would buy them if you like them. Keep a record, or at least a mental note of what you did and how they responded, and if they fail consider it a learning experience. But I can't imagine they will.

boman47k 06-30-2010 06:57 PM

Bought 3 at a different nursery today. Planted, pulled a few yellow leaves, and cut them back just a little. I will treat them with some 3-in-1 I have had a while and see what happens. Very few, if any black spots on them. Three 1 gal's at $32.

Had myh wife to call this place to see if they had them, and they had a few pinks left. The lady told my wife on the phone that people say thesew roses will not get black spot, but they will in our area. When I got there, she also told me that it would sometimes go away when planted, but I could treat them with the 3-in-1 I have, even though I have had it a few years now. But like I said, after pulling a few leaves that had yellowed and cut back a little, there are very few, if any, black spots on these.

Some of the first ones I looked at were pretty heavy with some kind of black spots.

Thanks for your replies, much appreciated. I was beginning to wonder if anyone would reply.

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