The AARS criteria had little to do with the natural disease resistance of roses since they were largely grown and evaluated in gardens wIth regimented spray programs.

If you want roses where disease resistance is the highest criteria, you'd be better off looking at roses with an ADR certification than anything with AARS. It is why the American Rose Society is looking at ways to emulate the ADR program in North America.

Kordes stopped spraying their field and new seedling roses with fungicides back in 1991 and any rose that was susceptible to disease was removed. Those that showed high resistance were used as breeding stock and for the next generation of roses. There's a reason they are by far the leading hybridizers of exceptionally disease resistant varieties that also have an emphasis on cold hardiness and bloom form and quantity.

What is ADR?

How does one know if a rose is a Kordes rose or not? Would that be on the label? (Not that I have even 1" for a new bush!!)

The ADR roses are mostly shrub roses and they are hard to find. AARS stopped spraying their roses in 2011. Natural disease resistance isn't a top priority for me, although the less I spray the better. There is a big difference between a rose getting B.S and blooming than one just dying.

I don't really know what ADR stands for, but understand that it is a term for testing performance of roses developed in Germany (?).

Try some Kordes roses. I have a number of the Fairtale roses, and each of them are super in the blackspot resistant department. If you like bareroot, Palatine is a good resource for Kordes roses. I don't spray, and each and every of them are barely bothered at all by blackspot. In fact, none of them havce any infection this year o far while some of my other roses are strugglig to hold down to their leaves. I was not crazy about them when I first got them (as I like Bourbons, Teas and Austins, and felt they are a bit "plastic"/"boring'/), but I have grown very fond of them the past 2 years.

The so-called Earth Kind roses are another option. You have some of those on your list. My guess is that Belinda's Dream and the Teas should do very well in D.C.

Being in the DC area, you probably have a lot more choices than here in Northern Jersey when it comes to what you can plant in the ground. I lived in Fairfax County for about 10 years, but I did not get in roses when living there. The only rose I grew back then was an Angel Face, which was killed probaly by neglect (or maybe it was blackpsot) its first year......

A lovely Bourbon/Noisette, Marie Dermar was completely BS free for me in upstate NY. Unfortunately, it was not hardy. I think many of the Noisettes are supposed to be BS resistant.

Another I have which so far has had has clean foliage right up until just before frost is Ivory Triumph. I hope another nursery will pick it up after VG closes.

Allgemeine Deutsche Rosenneuheitenprüfung (ADR) is a German program to assess roses for disease resistance. According to the web site (linked below), "The ADR varieties grown at the trial sites are cultivated with out any chemical pesticides to evaluate their natural beauty and strength." The evaluation is rigorous.

socks12345, a "Kordes rose" refers to a rose hybridized by Kordes in Germany. Vendors usually list the hybridizer in their materials. If not, look up the rose on helpmefind.com/roses, you can find the hybridizer name in the variety listing.

Here is a link that might be useful: ADR - Performance testing of new varieties of roses in Germany

The ADR roses are not mostly shrub roses. While it is true that is the prominent category of the winners, there are many ADR roses that are classified as Hybrd Teas, Floribundas, Miniatures and Climbers.

A small handful of recent examplesoff the top of my head include:

Roxy- miniature
Golden Gate- climber
Brothers Grimm Fairytale- Floribunda
Solero Vigorosa- Floribunda/ Groundcover
Eliza- Grandiflora
La Perla- Hybrid Tea
Golden Fairytale- Hybrid Tea
Grand Amore- Hybrid Tea

There are many, many more.

What do you spray "every three weeks?" It must be a home-concoction or an old-school spray like Funginex. Try Bayer Advanced Disease Control or purchase something like Banner-Maxx from Rosemania. Either of those will give 2-3 week protection from BS (there are places worse than D.C. for BS).

I have Scentimental (2 of them) and I have to hard-prune them to keep them below 7 feet. The damn things are invasive, too - with spreading roots that result in basals 2-4 feet from the center of the bush. I swear they're weeds!

billjoebob

have you been to see the National Cathedral's rose garden in the bishop's garden? beautiful and always inspiring. i wonder how they do it?

We have over the top humidity levels in Alabama and BS is a major battle here. I spray every two weeks with Bayer Advanced Disease Control. From your list, I grow Scentimental, Marmalade Skies, Wild Blue Yonder and Cinco de Mayo. All four respond well to Bayer for me...much better than anything else I have tried. Marmalade Skies does still get more blackspot than most of my roses, but not enough to be a problem.

I have been using Bayer Advanced Disease Control for my roses for the last two years. It did not meet my expectations and I still have a lot of black spot. I started spraying early this year and the black spot keeps spreading.We have actually had cooler than usual weather until the last few days, so I'm unsure why the black spot is so early and prevalent. When you use the Bayer Advanced, do you need to rotate it with another product?

Thanking you in advance for any suggestions.

Yes - the secret ingredient to use with Bayer is Pentathlon. Formerly known as Mancozeb (liquid) or Manzate (powder), the powder version is no contest when it comes to price. I really don't know why anyone used the liquid form - more than double the price because someone else mixed it.

Anyway, it was SOP around here a few years ago - or at least with Banner Maxx at the time, before Bayer got so plentiful. Pentathlon (formerly Manzate) is an absolute fungus contact killer. It will kill what Bayer will not - Botrytis, for instance. At the same time, it serves as a rotation, even though you mix it in with the same thing you're trying to rotate from (Bayer).

If you have a BS problem, start with Bayer + Pentathlon and it will absolutely knock down the BS. Continue with the Bayer once a week for 2 or 3 more times and you should have it licked. If not, another application of Bayer + Pentathlon will nuke the fungus for good.

BTW, michaelg can confirm this with greater detail (or the other Michael from Michigan), but BS needs temps down in the 60's-70's to really reproduce. If temps are consistently above 80-85 degrees all 24 hours or down to 50's at night, the BS won't survive .

I may have those temp thresholds off somewhat, but hopefully you get the picture. It's the in-between climate that's worst. ;-)

Can Manzate be mixed in the same tank as Honor Guard?

Of billjoebob's list, I have Scentimental & Cinco de Mayo and both do pretty well with regular spraying.

It's funny what you say about Scentimental's weak stems, because I had a Scentimental a few years ago that was weak and floppy. I lost it to an accident and replaced it last year. Even though it wasn't the greatest plant I loved the stripes and there aren't many substitutes so I gave it another try. The new plant is strong and vigorous.

Moondance, another AARS winner, is unquestionably my best floribunda and always has clean foliage.

The AARS winners were never promoted as disease resistant To me it was a marketing ploy saying that there roses were the best. Most of te AARS roses weren't that good Thank goodness the program was stopped!