The only thing you can do is try to cut out the diseased part as far down as possible. It may not have gone down to the roots yet. But you will then have to watch to see what comes back, if it still has signs of the disease. If it got into the roots, it could spread through the whole plant.

When you say layered, do you mean it has a separate root system? If so you could try painting RU on that root system to kill that separate plant. Only time will tell if it has spread to the other plants.

Its canes are coming out of the ground away from the main bush. I assume it layered from a branch that was once above ground. This is in hard soil, with other roots nearby, so I'm not sure what will be possible as far as getting rid of all the roots.

What is RU?

Thank you for answering.

How do you know that it is rose rosette virus damage and not herbicide damage? Can you post pictures?

RU is Round Up. It's a plant killer. That's why you "paint" it on and not spray it, so the rest of the rose isn't affected. Chancy for sure, but so is digging the roots, and non treatment is pretty much a guarantee to spreading to the rest of the roses in your garden.

Round Up, of course! I didn't know that would work on cut wood. I have a tree man coming this week (not for the rose). I guess he might know of some industrial strength thing to apply.

Carrie Helene, are you suggesting not digging around to get the roots of that layer?

It can't be herbicide damage because no herbicides have been used there. Also, it's mostly hidden under healthy canes, so spray drift would not explain it.

Nope, just saying any route taken is going to put the original rose at risk. Whether digging around in the root system or RU. If it was mine, I'd tear the whole thing out and burn it, but that's just me. Seen it in my garden before and that was my solution. Single rose bushes are replaceable. While it might hurt me to take out a gorgeous plant, it would hurt me a lot more to lose all my roses.

It does not have to be spray drift. The herbicide could of traveled underground through the moisture/water or root to root contact.

https://sites.google.com/site/roserosettevirus/

Thank you so much for the link to your article, Henry. I've looked at it quickly now and will study it tomorrow. I didn't know that application of phosphorus can activate glyphosphate in the soil. We do use glyphosphate, but have not ever used it or any herbicide anywhere near this rose. The closet application was downhill about 20 feet away. I'm thinking the slope would matter and the Roundup would not percolate uphill through the soil. Is that right?

Sorry, RU is roundup. You can paint the undiluted liquid onto the cut stem and it will penetrate the cut stem and kill the roots.

The following was stated: "You can paint the undiluted liquid onto the cut stem and it will penetrate the cut stem and kill the roots."

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H.Kuska comment: yes and then it will pass into the mother plant if the two root systems are still connected or it will pass into the soil and then may be picked up by the roots of the mother plant if the roots are no longer connected.

I would try cutting it out, is sounds like this part is from a "sucker" off of the original plant. You might be able to dig down and trace the sucker back to the original plant, I would go back as far as possible and dig out that amount. Good luck.

You don't have pictures, do you? I just wonder about herbicide damage and it is odd to me that the damage is closer to the ground from the sound of it. Round Up drifts 30 feet on a still day so a neighbor may have used it.

I'll try to take a picture of it tomorrow.

Here it is.

That is scary looking. If I understand correctly, this cane terminates on the original plant. You will definately need to remove it there and hope it is has not spread to the rest of the bush, along with digging it out.

What about this picture makes one conclude that this is rose rosette virus damage relative to herbicide damage or simply rapid new growth? When was the last time that this part of the plant looked normal? Were any of the mites observed?

Roundup can pass through a connected system. But despite Henry's repeated quotes of various scientific articles (usually related to edible annual herbaceous plants unrelated to roses or seedling growth in farmland) there is no real evidence that any transfer from roots to soil to roots in the sort of application we're talking about, can really harm an adjacent hardwood bush like a rose, not to mention a huge established shrub like the one we are discussing. People have been 'surgically' removing garden plants using roundup for ever. Most of it is bound rapidly to the soil (to the extent that cutting a stub and powdering with a little dirt before 'rounduping' greatly diminishes the efficacy of the herbicide) and what little may or may not end up in the rizosphere from where some may or may not be absorbed by adjacent roots has not shown any harmful effects under field conditions.

Now we have discussed this repeatedly before and I'm sure Henry will come up with yet a few obliquely related articles stating that traces of roundup or the results of its decomposition in the soil have mean identified in adjacent plants (and I have no reason not to believe this) but the field experience of millions of gardeners and farmers shows you can roundup a bush with the cut and apply method with no noticeable harmful effects to the adjacent ones. If there was a problem we would know about it through collective knowledge and word of mouth even if we didn't undestand the mechanics of it. I don't challenge what the linked articles are describing, I'm challenging Henry's crude interpetation and his arbitrary chain linking of them, which is grossly exaggerating to say the least. I'm sure Henry understands very well what he's reading but when someone is on a mission anything goes. There, I have vented off.

PS I have never ever sprayed roundup or any other herbicide in my garden for weed control and I don't intend to, but I have used roundup on cut stems and stubs of small bushes and large trees repeatedly when it was the only viable solution to get rid of the plant for whatever reason.

PS2 In the above I don't mean to recommend the roundup method for the particular RRV suspicion problem at hand. Firstly I have no knowledge or experience of RR disease and secondly I wouldn't do it myself out of fear of passing the herbicide through a possibly connected root system which, even if it doesn't kill the mother plant, it may cause symptoms similar to RRD which, for obvious reasons, would defeat the purpose of the original effort to save the mother plant..... I just commented on the use of roundup to kill individual plants.

Henry,

In your reading about herbicide damage, have you found any mention of trifurcating thorns emerging after the cane has grown? Especially along the cane at about 3 o'clock.

The near horizontal cane is really strange, in ways new to me. Perhaps you can help by pointing out the herbicide symptoms you see here.

When I've seen this cultivar sick with RRD, it's been much later in the infection cycle. The Silvestre and Chapman paper was based on a leaf from this cultivar with early signs of RRD and they found the virus in that leaf in different parts of cells.

I don't know what's going on with the thorns/prickles here. Any ideas?

Ann, one day I found a dead squirrel trapped in my New Dawn. I state this because in my experience New Dawn's thorns are wicked.

I cannot diagnose this as herbicide damage just as I cannot diagnose it as RRV or unusually rapid growth. A number of the RRV articles suggest looking for the presence of the mites. Of course this is also not definitive. The suggestion to remove this part to the soil appears to be an appropriate caution. However, if it is RRV it appears to have had sufficient time to pass into the roots (unfortunately, we do not know how long this part of the plant has not looked "normal".

nikthegreek: the original answer (as I understand it) is that it is still connected to the mother plant through the root system (this was a natural layering). Concerning travel through the roots, this is what is on the label:

"DO NOT MAKE CUT STUMP APPLICATIONS WHEN THE ROOTS OF DESIRABLE WOODY BRUSH OR TREES MAY BE GRAFTED TO THE ROOTS OF THE CUT STUMP. Some sprouts, stems, or trees may share the same root system. Adjacent trees having a similar age, height and spacing may signal shared roots. Whether grafted or shared, injury is likely to occur tonon-treated stems/trees when one or more trees sharing common roots are treated."

https://s3-us-west-1.amazonaws.com/www.agrian.com/pdfs/Roundup_PRO_Herbicide_Label5a.pdf

Does it happen in roses? See:

http://www.actahort.org/books/751/751_26.htm

The real problem with looking for the mites is that they are vagrant and also seasonal.

We first visited Dr. Jim Amrine out of season and walking around campus with him, collecting sick roses, he expressed doubt that we'd see the mites on most of the samples we took, but he did have one bush that had 'the right' mites when others didn't. Sure enough, it did. It was sort of down in a protected place, and there were lots of other very small...truly microscopic creatures there. The one that amused me was something square (looked like a pillow) with two very short legs at each corner....and it walked.

For the sick roses up at Elizabeth Park in CT, a plant pathologist finally saw the mites after the roses had had problems for several years. Going to the Kassar and later the Iowa State population counts (Epstein and Hill, and more recently Laura Jessee) on multiflora, some years populations don't swell at all, other years in those states, it's a late summer thing.

We cut out the layer today. Out in the open I was able to get a better photo. This cane still has some normal leaves.