Joebar, I doubt that grafted vs ownroot has anything to do with it. Hot Cocoa is considered relatively resistant. Some Austin varieties are fairly resistant, others are highly susceptible. Hybrid teas and probably 90% of floribundas will need spraying in the PNW. So will many Austins and OGR. If you aren't going to spray, you need to be very careful in selecting varieties, but you have a bit more latitude than we in the East.

Lynnette's excellent site might offer some useful guidance for your region.

Here is a link that might be useful: The Old Rosarian

First of all, let's clarify your terminology.

Austins are modern roses. If you order them from David Austin (and some other places), they are grafted. So "modern grafted roses" describes many Austin roses.

I think what you mean is modern roses like Hot Cocoa--in other words, hybrid teas and grandifloras. Many are grafted, others are not. Many, many of them--whether grafted or not--are susceptible to BS. A limited number are a bit more resistant.

As far as Austins go, some are real BS magnets, especially when grown in certain regions of the U.S. Doesn't matter whether they are grafted or not. A smaller number are more resistant and Austin even has some that are very disease-resistant, such as Mayflower and Mortimer Sackler.

In other words, it is hard to generalize because there is so much variation, but the one generalization most posters will probably agree with is that hybrid teas, as a group, are usually more BS prone.

Hope that helps.

Kate

With our dry summers here any rose that gets bs now was doomed to have an even worse case during the fall and in the spring when they leaf out without an extensive spray program. I have not seen any real difference in resistance to bs between grafted and ownroot bushes if they are the same cultivar.

There are more bs resistant roses being produced now but I have not seen any particular development in Austin roses against bs. He has produced some very disease resistant roses and a good number that need a spray program just to live.

joebar-which three austins did you buy?

Hi
Garndeners often use bark mulch and shredded pine and I am convinced that mulch can bring on black spot. It may be different with cocoa shells but I have not tried them out yet. I agree with what others write here, grafted roses should be just as healty and ownroot. Another facor is that newly planted roses some times are prone to fungus diseases and are often healthier the year after planting. Too much fertilizing can bring on fungus tool, especially lots of nitrogen.

Not all hybrid teas are the same, some are quite black spot resistant.