I have the new (2012) Canadian Artists yellow shrub rose, ‘Bill Reid’, planted in a small rose garden I maintain. It (actually, three plants planted together) is horribly infected with blackspot and mildew, and also the odd new cane makes the shrub very unbalanced in appearance. In contrast, ‘Morden Sunrise’ in the rose garden is quite clean and is a balanced (but stiff) shrub in its growth habit. Although the flowers maintain their yellow colour very well, this is a rose I can’t keep in the rose garden since it substantially subtracts the beauty of it. It seems we have a way to go to develop high quality, disease resistant, yellow shrub roses for cold (Zone 3) climates. I’m working on it.
Keep working on it, Bro.
Any rose worse than Morden Sunrise is bad indeed.
The color is obviously pretty, but I knew it was trouble when I saw the lineage. Morden Sunrise was problem enough, but adding lines from the whole Graham Thomas/Abe Darby/Golden Celebration/etc. spectrum is just adding insult to injury.
How hardy is Prairie Sunrise there, which is also from Sunsprite? I got a mildew-free seedlings from it, so it cannot be that difficult to get good things from, since my resources are limited.
I’m not sure if you were asking me or Paul or both, but I’ve never had Prairie Sunrise growing outside here. I have several seedlings of it in the field that can be evaluated as the years go by.
Dakota’s Song has been doing well here. Better than Winter Sunset (planted right next to it) or Prairie Harvest (planted in a less hospitable spot). It also kicked the butt of Morden Sunrise planted near it.
Thanks for mentioning the lineage. It’s set me off on a HMF spree. I should also search this forum for Sunsprite, as I seem to remember folks bad mouthing it in terms of passing on blackspot susceptibility.
Speaking of the search for a hardy yellow, I have a few hips from John Davis pollen setting on First Impression, Cal Poly, and Sparkle n Shine (which, btw, seems to be a very good hip-setter). I’m hoping for something like Terry Roszko’s beautiful Morden Sunrise x John Davis, minus the Morden Sunrise genetics.
And a fat hip on Cal Poly from Leafland Double White Altai. Fun!
Paul, any updates on your work with John Davis?
I am mostly asking whoever will answer and is interested, lol, but specifically northerners.
Sunsprite is a decent plant in its own right, especially because of its major attributes. The bad part about it is from what Golden Masterpiece brought in with it, which is tissue weakness and awkward stems. That isnt to say that those issues cannot be bridged, but it is good to be aware of those issues when diving in.
Prairie Sunrise was not very healthy for me. Prairie Harvest has been far better. I have quite a few PH x Julia Child seedlings this year that are looking good. I had Morden Sunrise for about 2 years before it died. I was able to get 2 MS x Home Run seedlings from it that are quite healthy, but they are not yellow.
Liz
Prairie Harvest is gratifying as a seed parent because its hips quickly swell to fill their wrappers and have a lot of seeds.
Joe,
Your reference to Terry Roszko’s disease resistant ‘Morden Sunrise’ x ‘John Davis’ yellow selection is very relevant to this discussion. Incorporating Rosa kordesii cultivars in a yellow rose breeding program, unless it is at a diploid level, is almost a necessity I think to obtain disease resistance. At least for the Canadian Prairies, where the Explorer Rosa kordesii cultivars generally have very good disease resistance. ‘Champlain’ is an exception; it is quite prone to mildew in the latter part of the summer.
I still use ‘John Davis’ in my breeding programs and actually should have used it a lot more this year (I will next year). My best crosses with it this year are likely ones I did with ‘Rugelda’. But in an attempt to get shorter yellows than Terry’s selection, I’m also using ‘Louis Jolliet’ as a staminate parent with, for example, ‘Morden Sunrise’. It’s more tedious to use, because it’s not nearly as productive of pollen as ‘John Davis’.
I have a ‘Prairie Youth’ x ‘John Davis’ selection that should bloom for the first time next year. It has attractive, disease resistant foliage. Likely a Pillar rose in a Zone 3 climate and perhaps a Climber in a warmer one.
My Bill Reid is presently in the process of breaking down from blackspot–another week and the foliage will be pretty much gone. In spite of that, I actually enjoyed the plant for much of the summer and it was slower to defoliate than Morden Sunrise was in my garden (usually by the end of June). The eight new Austin roses I was trying defoliated far more quickly than BR. My Bill Reid is not yet winter tested but, if it shows better hardiness than Morden Sunrise, I think it could still have value in a hybridizing program. I’m not ready to throw the towel in on it quite yet and intend to give it a bit longer evaluation.
Paul, you are right that the Explorer Roses could be used to enhance the general health of roses like BR. But I am finding that the leafspot diseases are becoming an increasing problem in my area and David Z could confirm that fact (yes, I know that everyone has heard this lament from me before but it is a serious problem here). There is very little in my garden that has not broken down and defoliated to at least some extent from LS–the main exceptions are plants in the garden for less than three years. My John Davis is presently 60% defoliated from leafspot. I still use it in hybridizing but most of the seedlings that are initially clean will usually break down in year three to year five. It is frustrating as a rose you presume to have excellent disease resistance is slow to show the signs of leaf spot–but the effects can cause defoliation as severe as blackspot. As an example, I do a pretrial testing/screening for David of roses for the northern Earthkind Trials. The roses submitted for testing have improved significantly since the trials began and show far better disease resistance than was the case even a few years ago. However, those screenings run for two years. I hung on to a few of the best roses to test for an additional third year. Nearly all of those roses showed significant infection with leafspot this year and I can predict that in another year they will be defoliating from the infection if they haven’t already. I believe that leafspot has always been present but is not quite as infective as blackspot. The organisms did not cause serious issues because the plants usually defoliated first from blackspot infections. I think that the leafspot organisms are weaker pathogens. But, as roses improve in blackspot resistance and hang on to their foliage, I believe that this foliage is now open to infection by leafspot organisms as there is not a competitive organism present. Infection occurs at the same time as blackspot under similar conditions. As those LS infections increase year by year, the inoculum in the environment also increases. It is hard to know where to go with this from a hybridizing perspective.
Paul, until recently, I had touted the disease resistance of ‘John Davis’ … it has looked like this the past two summers and I’ve dropped it from my breeding work 
Julie, most of my ‘JD’ offspring have also become progressively defoliated and now show bare legs up to their necks … that’s unfortunate, as many of these have very attractive blooms in sunset shades and upon winter hardy plants. I now realize those from my '‘Morden Sunrise’ x ‘John Davis’ crosses have really gotten it from both ends when it comes to being disease prone … though, my yellow selection and the one shown below have held up well, at least so far, lol. This frilly beauty has very nice foliage, repeats well and shows little dieback in my protected zone 3 garden. I’ve crossed it back onto ‘Morden Sunrise’ in the hopes of developing a hardier more disease resistant ‘MS’, I can still hope, lol.
Great to hear from you, Terry! Thanks for the pics. Morden Sunrise and it’s offspring are frustratingly lovely, eh?
Julie, when you say “there is very little in my garden” that has not broken down from leafspot, could you mention what that very little might be? Any species roses, for instance? We need to start somewhere.
That LS problem is indeed a little disheartening and depressing. I don’t seem to have it here, so I have no way of starting to breed for resistance. I wish there was a way to inoculate my plants. William Baffin, for instance, is still completely clean here. How are the Radler roses? For instance, Morning Magic, in relation to another recent thread. What about R. virginiana?
Joe, reading your post and looking at the spotted plant, the thought struck me that perhaps Nature provides greater black spot pressure where roses would more likely be killed by cold than she does in more benign climates, and perhaps the reason for that is to help force the roses into dormancy?
Is that even black spot?
Terry,
I’m very surprised to see the photo of the diseased ‘John Davis’ you submitted. I’ve grown this cultivar in several Edmonton locations and propagated it many times. I’ve never seen plants of it diseased to any extent. I checked a couple shrubs of it this afternoon I planted in my neighbourhood a couple years ago and they are clean. Even the one that has been neglected by the owner of it. One of the most beautiful shrub roses, ‘Lambert Closse’, was developed from 'John Davis, using the yellow Floribunda ‘Arthur Bell’ as the pistillate parent (it would be interesting to repeat this cross and see if progeny having yellow flowers could be developed). I’ve never seen ‘Lambert Closse’ infected with disease, wherever I’ve seen it grown.
I think it’s possible rural areas (like yours) can be a factor in roses being susceptible to disease. For example, a few years ago it was impossible to grow ‘Morden Fireglow’ at the Devonian Botanic Garden rose garden, because it was so susceptible to blackspot. ‘Morden Sunrise’ was also very problematic to grow at this location. Yet both cultivars have been disease free growing in the urban environment of Edmonton. Why this situation is, I don’t know. I can only speculate that maybe the humidity at night is higher in the rural environment, and therefore it could be a determinant in causing rose diseases.
Here in my part of the Twin Cities, things have been going from bad to worse. Leaf spot (as shown in Terry’s photo) was rampant last year and we’ll soon see if it will be as bad again as we are getting into that season. Lambert Closse–lovely rose!–is already showing leaf spot on the leaves remaining after its bout of blackspot. I’ve got blackspot on some Rugosas that were healthy in previous years (most notably Schneekoppe, to my deep regret). Aesthetically I am trying to ignore it. From a hybridizing perspective I’m all ears to find out what is clean in everyone else’s gardens!
However, the yellow and brown leaves caused by the drought, along with the fungal disease patterns on the foliage that is still green, the ripening hips, and the colors of the flowers themselves make for a very bright display at this time of year…
Wow–I have posted a fairly lengthy reply to this thread twice–I’ve previewed it and hit post message–the response has just completely disappeared two times! Are they hovering around in RHA cyberspace somewhere?
I’m sorry Julie. They’re nowhere I can see. That’s why, both here, HMF and GW, I often write my responses in an email so I can check spelling, copy and paste it where I want it. Should something hiccup and not post, at least I have what I’ve worked on to copy and paste again. Not QUITE as frustrating that way.
Julie-Not sure if this happened to you, but sometimes there seems to be a “timer” on these posts-I got cut off once when I took a phone call (or answered the door or something) and when I came back to the computer there was something on the screen (this only happened twice-I’ll take notes next time) that indicated that I had timed out. Once it was on the personal messaging service, and I hit send and that one went through, but the other post got deleted. I took that to mean that I couldn’t just take all the time in the world and maybe I better have an idea about what it is that I am about to say. Don’t know! Maybe this is from my computer and not from the forum.
sympathetic frustration
I’m not a real tech guy, but it might have something to do with a time-out as Jackie suggests, especially since your reply was lengthy.
Sometimes what I do in these situations is to highlight what I’ve written and press Ctrl-C (Command-C on a Mac) to copy it to the clipboard before clicking anything…
Please don’t give up…I want your knowledge!
Joe
I’ll have to try to do my message one more time–I’ll do a Word Document and then cut and paste it so I don’t lose it again. I didn’t get a timeout message–which I have seen before and the site even said there were two messages to post–they just didn’t post when I hit the button. But, I suspect that it was really a time out issue. These post times are probably not open for very long since most messages are fairly short.