Are there any of the Morden series that are disease resistant?
I know the conditions are completely different, but in the mid desert, Morden Blush was bullet proof.
Thank you Kim. Unfortunately, Morden Blush gets BS here. I do have Paul Olsen’s sport of Morden Blush, Prairie Snowdrift, which has very good resistance here and sets hips. I was hoping to obtain one of the Morden Series that has very good resistance as well to work with. I get the impression that much of that series lacks resistance. Thanks again!
You’re welcome, Rob. Blush was the only Morden that didn’t contract SOMETHING in that climate. Ruby was gorgeous, until it RUSTED.
I looked each one up on HMF and noticed that they all, except for the once blooming Morden 6910, are noted to be prone to BS. Maybe I should work on my own using the R. arkansana ‘Peppermint’ that Kim gave me.
Interesting. So, they were focused on hardiness instead of health? Or, are they mutually exclusive? Are black spot (and other spotting) and rust susceptibility necessary for greater hardiness? Perhaps to help push the plants into hardening off once the water supply indicates “it’s time”?
Hi Rob,
Instead of using Morden roses, how about trying one of the Explorer roses?
I find they are more disease resistant than the Mordens. I still sometimes use Morden Blush if I
acquire some species rose pollen. MB is very fertile and the seeds germinate easily.
The best all-around Explorer rose for hybridizing, I find is George Vancouver. It sets tons of seeds, and the seeds germinate easily.
One weakness of GV, its foliage is coarse, and the plant leggy. These traits are passed on to its progeny.
chuckp
Good question Kim. Could it be R. arkansana that is the issue? I’m guessing that BS wasn’t much of an issue in Morden, Manitoba where they were being developed. If that’s the case maybe the temps up there kept BS to a minimum?
Chuck,
Thank you for your suggestion. I’ll have to research the Explorer roses more. A quick look at George Vancouver on HMF showed that it lists GV as “susceptible to black spot”. How does it perform for you in that respect?
Kim and Rob,
The Mordens have a pretty good dose of R. arkansana in them, and with that comes susceptibility to rust. Rust is unsightly, but it does not kill plants in the northern zones. All the native species in Manitoba are susceptible to rust. Yet they survive and thrive.
Survival and plant habit were two of Henry Marshall’s objectives, but the essential consideration was survival. A rose that did not survive was of no use.
Disease could be tolerated if the rose lived and bloomed well in the short summers of Manitoba and the other prairie provinces. Black spot does afflict the Morden roses, some more than others. Perhaps the strains of black spot in Morden are not the same as those where you live or have lived. Certainly most parts of California and Rob’s area of New Jersey have different levels of disease pressure–and probably different strains of black spot. After all, 16 or more strains have been identified. Some rose varieties are immune to one or two strains, but fail terribly when another strain arrives on the wind or on potted plants shipped cross-country. Other varrieties have moderate resistance to several strains of black spot.
Some of those highly resistant modern varieties are descended (even if distantly) from varieties that were chosen for color or flower form instead of disease resistance. And, yes, I am including Knock Out and its descendants.But those roses were built on generations of parents which had been inoculated with many forms of black spot and only the survivors kept for future use as parents.
It’s all a big gamble. Location, location, location–and constant testing–will bring into existence more varieties with broad-based disease resistance.
Choose parents well, breed, cull, and hope. And repeat. And repeat.
A variety with good fertility helps. So go ahead and use Morden Blush or another of the fertile Mordens. Just don’t expect one generation to produce the next Knock Out. And don’t disqualify a potential parent just because it gets some black spot. There are some things worse than black spot.
Peter
Peter, You said it much better than I could.
Rob, what I did since I started breeding roses 20 years ago this year. I started off with the Mordens
like Adalade Hoodless and Morden Centennial. I crossed them every which way I could and planted out the seedlings.
As Peter said, you need large numbers to select out the few seedlings that show promise.
I am not aware of how much space you have to work with. But something you may try is to cross a few of the Morden roses with some of the
Explorer roses. This is a long journey, it’s going to take time…and resources.
chuckp
Thanks, Peter. I’ve long believed our obsession to eliminate disease is a perfect fool’s folly. Rust, in particular, ‘tells’ Arkansana when to shut down and go dormant. I taught myself that by drying it out here and observing heavy rust, even on new growth. Increasing the water resulted in a flush of new, completely healthy growth. Allowing it to further dry out caused heavy rust. That was a yo-yo I could repeat numerous times a summer into fall. The only logic to it was when ground water begins to dry up, it means “winter” is coming. Rust “tells” the plant when to shed the foliage and shut down so it’s “Arctic hardy”. That’s why the only Arkansanas I will even allow into the yard here are Peppermint and Woodrow as neither of them rust in my conditions.
Thank you Peter. You gave me much to contemplate and what you wrote makes so much sense. I do have Paul Olsen’s Prairie Snowdrift which I will consider a “Morden” as it is a sport of Morden Blush. It has very good resistance to BS here and tolerates what BS it does get very well. Last season was my first with it and so far it appears to be fertile as a seed parent. I forget if I tried it as a pollen parent and if I got anything from it. I have a seeds from crosses in the fridge.
I also have a few Explorer roses; Frontenac, Quadra and Royal Edward which are nearly disease free here and I can combine them with Prairie Snowdrift. That should produce healthy and very hardy seedlings…hopefully.
Then there are the Canadian roses that I have; Campfire, Canadian Shield, Never Alone, Radler’s Ramblin Red and the hybrid Kordesii, Cape Diamond, that I can add into the mix. Looking at my list I have some good genes to play with.
Thank you Chuck. Right now my space is limited to I’m trying to stock my breeding pool with the healthiest and hardiest breeders and not expecting tons of seeds. I actually have seeds that I won’t be able to stratify this winter due to space limitations in my refrigerators.
See my text to Peter regarding your suggestion re: crossing Morden roses with some of the Explorer roses.
Kim,
I’m glad to read that you indicated 'Pepperment" doesn’t rust. I was wondering if I would keep it due to arkansana being known to rust. I also have David Z’s Ark-OP. Do you know if that rusts? Thank you.
I don’t know about David’s Ark., Rob. I haven’t grown it.
I haven’t seen rust on Ark-OP, but we don’t typically have too much rust here. This one seems to be a hybrid with something neighboring (likely one of the Carefree BeautyTM seedlings growing nearby). It is an op of a stippled Rosa arkansana I dug up along the highway in Morris, MN.
Hello David. I’ve not seen rust on my plant here either. Thank you for the background information on your arkansana hybrid. I plan on using it for the first time this season. Can you give me any suggestions on the best way to use it as a parent? Passing on stippling would be very nice!
Ark-OP sounds as if it is along the lines of Peppermint, from the stippling all the way to rust resistance.
Luckily I have both of them. 