Garden

[blueroses47]

I have six red knockouts in front of a fence in my front yard.  This was the third year that I had them, and this spring they did really well in terms of bloom, very pretty.

Well, about a month ago,or maybe even two months ago, I noticed a strange growth pattern on one of them, strange branching with lots of little tiny clusters of blooms.  I really just thought it was an end of the season type blooming...it didn't look "sick" or diseased, so I ignored it, but finally I got the chance to look it up on google, and apparently it's a virus called "rosette disease", and the advice was to yank the plant, destroy the plant entirely (don't add it to the compost pile, for example), clean up the ground well, etc.

I cut everything off....it had spread to one brance of the neighboring plant.  I am hesitating to pull the plant, I'm thinking maybe winter will kill the virus entirely. 

I am going to do more research, I just haven't had the time yet, and I was wondering if any of the gardeners here on the Q boards have had any experience first hand with this disease.

I hate to think I might lose all the knockouts near this bad plant. 

[sweetee2]

Was the tiny roses the same color as the bigger Ones? I'm wondering if it was the wild part of the rose growing out. I thought all roses are grafted onto a wild rose. Sometimes you will see a rose bush that has not been taken care of or has winter killed you will see little starts growing from the base it is growing from the original  rose graft, usually small red flowers. Just a thought.

[JustJazzmom]

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@blueroses47 wrote:

I have six red knockouts in front of a fence in my front yard.  This was the third year that I had them, and this spring they did really well in terms of bloom, very pretty.

Well, about a month ago,or maybe even two months ago, I noticed a strange growth pattern on one of them, strange branching with lots of little tiny clusters of blooms.  I really just thought it was an end of the season type blooming...it didn't look "sick" or diseased, so I ignored it, but finally I got the chance to look it up on google, and apparently it's a virus called "rosette disease", and the advice was to yank the plant, destroy the plant entirely (don't add it to the compost pile, for example), clean up the ground well, etc.

I cut everything off....it had spread to one brance of the neighboring plant.  I am hesitating to pull the plant, I'm thinking maybe winter will kill the virus entirely. 

I am going to do more research, I just haven't had the time yet, and I was wondering if any of the gardeners here on the Q boards have had any experience first hand with this disease.

I hate to think I might lose all the knockouts near this bad plant. 

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Yes, sadly, you must remove the entire plant. It is spread by mites that carry the disease from multiflora roses (wild roses). Read anything written by Ann Peck who is an authority on the disease. You must make sure to get all the roots out and do not replant a rose in that spot unless all roots are out.

What you saw with the multibranching is called 'witches broom' a characteristic of RRD (Rose Rosette Disease) and you will see stems remaining red in color and not turn green or woody over time, and you will see hyper prickles -- excessiveness of their prickles on those affected stems. Use the unaffected plants or other side of the Rose bush to compare the distances between prickles.

Winter will not kill the virus, once it's inside the plant it is inside the entire plant from roots to branches, Be on the lookout for this disease on your other roses -- monitor them. There is no cure or spray to stop it. 

As you observed, you will see smaller than normal shaped blooms. If you go to Houzz dot com on their Gardenweb site under roses, there are threads discussing it with photos from various posters -- some photos are accurate for the disease and some show evidence of herbicide damage. Read comments to learn more. 

I have had experience with it on 2 of my roses -- a Hot Cocoa and a Double Knockout. The Knockout had smaller than normal blooms as compared with Knockouts over at a Extension Demo garden -- that is how I was able to compare-- it got completely removed. The Hot Cocoa also along same fence line about 4- 6' away had the hyperprickles -- reminded me of a hedgehog, red stems and smaller than normal blooms on ONE SIDE of the rose bush. This also got trashed. 

Only insects I ever saw on them were aphids in the spring. The experts are not sure if aphids are also a vector or do mites hitchhike on aphids and infect the roses? Not enough research to determine this yet according to Ann Peck who I did e mail about my rose (Hot Cocoa).

I did replant roses in those areas after waiting a year -- a rugosa rose called Blanc Double deCoubert and another Double Knockout.

[JustJazzmom]

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@sweetee2 wrote:

Was the tiny roses the same color as the bigger Ones? I'm wondering if it was the wild part of the rose growing out. I thought all roses are grafted onto a wild rose. Sometimes you will see a rose bush that has not been taken care of or has winter killed you will see little starts growing from the base it is growing from the original  rose graft, usually small red flowers. Just a thought.

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No, no roses are grafted to wild roses -- most grafted roses are grafted to a Rose called Dr. Huey a tall gangly rose that is red in color. If you see a rose change color and you know your rose was grafted, this means the graft union has failed and the rootstock is growing and taking over. 

[blueroses47]

Thanks JustJazzMom, for all your information. I'm sure, from photos, that my roses have this particular disease, there's no doubt in my mind. 

I'll pull out both infected bushes.  The other four don't exhibit any problem, but I'll keep checking.

I'm bummed out about this, of course.  The row of red roses looked so pretty in front of a white picket fence.

Do you think I should try replacing the infected bushes next year? or is that too soon, do you think?  If I don't replace them, I suppose I'll just have to try something else temporarily in the vacant space....though right now, I have no idea what that could be.  Maybe I'll just have to leave it empty. 

I hope I don't lose any more of the bushes. 

I've been gardening for years, but just can't develop a good attitude toward losing plants.  You think I would be used to it by now.

Thanks again for your reply.

[JustJazzmom]

@blueroses47

If you must plant something now, plant a shrub. I try to avoid as much as possible, monocultures. Try looking for a dwarf fothergilla or a viburnum --pretty much pest free.

[blueroses47]

I was thinking about a shrub also, just a while ago when I was outside digging up the infected bushes. 

Or, I may try inserting a few clumps of shasta daisies that have been doing well for me and that seem to need dividing every year.  Maybe I'll make the long bed a little wider and place clumps of the daisies here and there at intervals.  I wanted to keep this area a little simple since it's in front of a mixed herb and cottage-garden flower bed that the picket fence encloses.

I'm trying to remind myself that gardens are constantly changing things and to take this in my stride.  As I said in my original post, the bushes looked so pretty this year that the thought of losing all the roses made me sad.

[blueroses47]

sweetee2,

Forgot yesterday to thank you for replying and trying to help.  I do think I definately have that rose rosette problem.  Unfortunately.

[dbeaud]

 I have been growing roses for 45 years and sadly, last year, I lost over 40 rose bushes to Rose Rosette. I have 3 bushes left and I doubt that they will be spared. PLEASE look up Rose Rosette and keep a tight eye on your rose bushes. It is very easy to identify and you must pull the entire affected bush, roots and all very very carefully to avoid shaking and spreading, and bag them immediately. The disease is caused by a virus and transmitted by mites and wind. Texas A&M University along with many many agricultural centers accross the U.S. and Canada are studying it and so far have not come up with any cure. I hope that QVC refreigns from selling roses, any rose, and The Knot Out Rose is NOT the culprit, it simply is very susceptible to the virus.

I will resort to plants like hibiscus, greenery and some flowers and I miss my rose garden......