Insecticides have no effect on RRD carriers. The disease is carried by a mite, not an insect. Insecticides and miticides should not be sprayed as a preventative. If you choose to spray insecticides or miticides use only when a harmful identifyable insect is present.
It's highly possible the disease was carried in after you planted your Knock Outs.
The only guarantee they can really offer is for Rose Mosaic virus and fungus diseases such as mildew, and blackspot. Even then, the fungus diseases can arrive on the wind soon after you plant.

Do you have pictures of the Knockouts you think have RRD? Perhaps it would help to have them assessed by others also--just for reassurance. It's possible they may have another kind of problem after all.

Kate

I don't have any pictures, but if you look up RRD on knock outs it was identical. The strange growth spurts, the red tips, excessive thorniness, the sepals were so elongated that they looked like leaves and often wouldn't bloom and if they did the rose was very deformed.

I am pretty certain of the diagnoses, I am just worried about my other roses. The main portion of my collection is in my backyard, while these are in the front. I have some climbers on my porch and 2 austins in a raised planter. I only bought knockouts because of all of my shade in front of my house and heard they would do well there.

grace e

About your other question, I think Chamblee, Roses Unlimited or David Austin are all first-rate nurseries and I would not hesitate to order from any of them. My personal preference is for Roses Unlimited, but I don't know if I have a good reason for that preference. I just love opening their boxes and seeing the roses already in bloom. On the other hand, I have to wait until after mid-May to get them--which is 3-4 weeks later than I usually plant, at the latest, my other roses.

It is very upsetting to discover RRD in your garden--it's happened three different times in a three year period in my gardens, but fortunately only one plant per year--but still, that is upsetting. I'm no RRD expert, but I don't think you need to worry very much about plants close by "catching" the disease. If the wind blew the mites off of the roses that got RRD, it probably blew those tiny, tiny critters half-way into the next county, not a couple feet away to the next rose. At least in my garden, the roses near by the infected rose never exhibited RRD symptoms. The next year when another rose came down with RRD, it was way on the other side of the back yard. Same thing with the third year when a third rose broke out in symptoms--way far away from the two previous ones.

I don't know where my disease-causing mites are blowing in from since I live in the middle of a small town, but I'm assuming it is from the wild stuff growing outside of town, not from other roses in my garden--since I immediately get rid of any infected rose in my garden.

As the other posters noted, spraying will not help the problem.

As upsetting as RRD is, I think you should just go ahead with your garden plans, assuming everything will be all right--since there is not much you can do about RRD other than destroying the infected plants.

Good luck.

Kate

Because RRD can spread so insidiously, I would go ahead and remove the ajoining rose. Better to lose that one than several more. I lost 15, mostly knockouts, although the first diseased rose was a floribunda named Julia Child which I had had for 4 years before it showed the disease. If you can't bear to remove it, consider cutting the canes way back. I think I read that the mites can overwinter under residual folliage. Finally, carefully inspect any new plants for signs of RRD. I have seen several nursery roses that have aroused my suspicion. Best of luck-Donna

It is important to not mix up herbicide damage with RRD virus damage. Some/many? of the observed problems may be due to the use of Round-Up type weed killers near the roses. The Round-Up can leave the roots of a weed, pass through the soil, and be picked up by the roots of nearby rose bushes.

See the 2 links below for Round-up spread:

http://www.agron.iastate.edu/news/events/2011staniforth_sm.pdf

AND

http://www.springerlink.com/content/t7h6601566432076/

Get rid of the infected roses and hope it doesn't show up on any others. That's what I do. It's really your only choice, so it makes the decision easier.

RRD is scary! I remember being completly freaked out when I first saw it in my garden. I bought some miticide but couldn't bring myself to spray it. The warning on the label was scarier than the RRD! I don't believe it is available to the average gardener any more.

Three large Knock Out roses near me died from RRD. Took them three years to die and, as near as I can tell, they did not infect any of the 6 roses in my garden. I tried to save a Belladonna OGR rosebush with RRD by cutting out the infected canes. After 4 years I had to admit defeat and dig her up. However, she did not infect anything else in my garden.

Be vigilant and have your pruning shears handy for new distorted growth. Don't give up! Some gardeners lose 50+ roses, but most of us only lose a few at at time.

Austin, RU, and Chamblees have been good for me for years. I lost one( local nursery) to RRD about 3 years ago, removed it and just replaced it last year with a Wedgewood Rose. I am watching that spot very closely. Isolated spot with evergreens nearby.

Have you read any of Ann Peck's writings on RRD? If not, google her. She's a wealth of information on the disease.

IMHO RRD is one of those things that we will have to adapt to, keeping vigilant on its' reappearance. I seem to lose 1-2 plants a year. I can live with that.
A few years ago I offered to check rose plants around the city. I even rooted out a few.
Ann is the go to person on RRD.
F.L.

You may want to check up-wind and nearby your house to see whether you can spot any RRD infected plants being grown by the neighbors, in commercial plantings, or whether there are any infected multiflora growing in wooded areas, fields or roadside areas within the vicinity of your house. If you can kill (or educate the neighbors to kill) any infected plantings nearby it will reduce the possibility more plants will become infected.

Another thing to consider is that the location where these roses became infected may be one where roses will be prone to getting the disease, due to the location relative to winds/walls. I have a couple places in the yard where big climbers in particular act as RRD magnets because the mites tend to be blown there on our typical prevailing winds. I have had to retire those spots from rose planting.