Chrysler Imperial thorn variability?

I am testing Chrysler Imperial as a seed mother this year. I noticed that certain canes are not so thorny, and others are super thorny. As far as I can tell, they are all coming from the graft or above it.

Can any forum member share their experience with Chrysler Imperial thorniness? And is the rootstock typically very thorny?

The images are from the same bush:

  1. A super thorny cane
  2. A moderately thorny cane
  3. A not so thorny cane

    [attachment=2]Chrysler not so thorny.jpg[/attachment]
    Chrysler super thorny.jpg
    Chrysler other thorny cane.jpg
    Chrysler not so thorny.jpg

I do not know about Chrysler Imperial but I have noticed the same thing with other roses. I have always wondered if you took only bud wood from these less thorny canes what would happen.

Personally, I would worry about rose rosette disease if I saw that many thorns of odd shape on a classic HT. With species hybrids, just par for the course.

It is a waste of time to work with classic, out of patent HT’s and floribundas unless your copy is VID. In my experience roses from bix box stores are worse than worthless as breeders because they are heavily virus infested.

Don, I buy all of my roses online from either Jackson/Perkins, Heirloom Roses or Edmunds Roses. I do not buy from retail stores.

Central NJ zone 7a

But did they say VID on the label? Call them and ask.

Larry, thank you for the heads-up about rose rosette disease. I never encountered it before. Hopefully I have caught it in time to save my other roses. If not, this is going to be a very expensive fix.

Central NJ, zone 7a

I am reviving this old thread because this is exactly what I am observing on Huddersfield Choral Society. I have two plants of HCS and the same is happening on both.

Acquired in bare root form in January from Dutch seller Tuincentrum Lottum.
First new canes grew thick and nice, up to about 70/80cm tall, smooth with a few big red thorns, matching the canes at the bottom.
As of about a month ago, as the first flush was ending, fast new growth. These new canes are incredibly thorny. I mean, ridiculously so:
These are growing well above the graft union, so it’s definitely not the rootstock (laxa).
Could it be due to fertilizer? I’ve been giving all my roses supplements of silicone and extra calmag these days.
Is there something else that can be causing this?

It CAN’T be RRD: there’s no RRD in Europe, right?.. Right?

I remember this precise discussion years ago about Reine des Violettes, many years before RRD became a real issue. The convention wisdom of the time was to only propagate from the prickle-free canes as that was reportedly how the prickle-free RdV arose. Not having explored that, I can’t confirm nor deny, but that was the discussion at the time.

Many years ago I read about Nicholas Grillo’s success in raising thornless roses. I vaguely recall that he did it largely by finding the canes with the fewest prickles and using only these for propagation. He did very well at it, and even crossed among the thornless selections to get even more smoothies. Most of these are listed as “sports”, but to get so many random variations suggest that he was very, very, very lucky. He worked with various sports and seedlings derived from ‘Columbia’, which is not very prickly in the first place.
Here is his HelpMeFind entry.

On the other hand, I have a more definite statement from New Zealand:
American Rose Annual (1984) p. 37-43.
K. J. Nobbs
Auckland, New Zealand
“Nurserymen have evolved for themselves thornfree stocks, for no one wants to work with thorny stocks. This has been done in western Australia and probably in Florida with the rose R. X fortuniana. This rose, thought to be a cross between R. banksiae (thornless in the double form) and R. laevigata, the Cherokee rose, produces for me shoots with thorns and at the same time, shoots which are quite smooth. Nurserymen, by selecting cuttings only from the smooth stems, ultimately in a few generations acquire a thornfree stock.”

Smoothness seems to be a tricky trait. It may be hereditary, but not really genetic. On one visit to the Burbank House in Santa Rosa, CA, I saw a bed of “thornless” Rosa multiflora … with the meanest looking example of the species I’ve ever encountered. Coincidentally, there was also an excessively armed branch growing from one specimen of Burbank’s spineless Cactus.

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Many varieties do this. Color Wonder descendants commonly do this. Stormy Weather seedlings have done this on me.

As long as its not actual RRV, its not really an issue. Annoying, yes. Issue, not so much.

Also seems to happen if a plant is sending out a basal and the night time temps dip. At least in my climate’s experience.

Prickle-lessness can sometimes be genetically superficial. Meaning – found in some outer layers, but not in sex cells. It is still somewhat of a quandary, and in roses there seems to not be a one-size-fits-all inheritance.

Fascinating, Karl K! So thorniness can vary within a cultivar.
And so I guess, if nurseries select smoother cuttings to sell less thorny plants, the plant’s new shoots could still revert to their original thorniness.
I guess that makes sense… I’m just surprised because it’s not just the stems, even the buds on my HCS are different with very rigid, thorn-like glandular hairs.
Would thorniness selection by nurseries affect bud appearance too?
This is more pronounced on one of my two HCS than on the other, although they are both exhibiting the super-thorny stems.

HCS buds before (old pic from first bloom in my garden):
HCS buds now:
I have a theory but it’s pretty farfetched, so I’ll keep quiet for now to avoid being ridiculous if there’s a straightforward explanation, like fertilizer or weather or something.

When I first read about all of Grillo’s thornless roses, I thought he had hit on a universal rule. But all his roses turned out to be ‘Columbia’ sports, sports of sports, crosses among sports and so on. Vegetative selection can be useful, but the plasticity of one “gene pool” or lineage may be different from others.

Some varieties can be improved in vigor, or the quality and quantity of blooms. Some are more resistant. For instance, after much success in improving the vigor of roses by careful bud selection, Bosley (1937) failed with ‘Radiance’. Of course, ‘Radiance’ had not declined in vigor despite large-scale propagation. It was born strong, and stayed that way.

Degree of “thorniness” can also vary with the degree of mutation toward a climbing sport. Rather than repeat myself, here is an article I wrote about Iceberg (which happens to be a variety which has been used several times to create low-prickle types) and how Mlle Cecile Brunner, a rose rather similar to it in breeding, follow that example. Poor Old Iceberg

Thank you for sharing the link to your article @roseseek, I really enjoyed reading that.
And I agree Iceberg doesn’t get enough love, I guess people find her too basic.
I have her and she is by by far the most bulletproof rose in my garden. Not only is she a bloom-machine, she stood up to four gale-force salty, sandy windstorms this April without defoliating or any broken canes, outperforming even my rugosas. A rose I love and respect!
I’m not sure any of this explains what is happening with HCS though. Those don’t seem to be climbing canes, and all new growth is like this. Both of my HCS are changing to super thorny simultaneously, and one of them suddenly has completely different, hairy/thorny sepals on her flower buds. I am waiting for those buds to open, I just hope the rose inside will still be the same as before and not some proliferated monstrosity.

I’m glad you enjoyed it! Can you post more photos of the suspect growth parts? I wouldn’t think it possible something like RRD would have made it to Malta, but Heaven only knows what kinds of shenanigans people have pulled…

Kim, I would be surprised if it was RRD too, and I sincerely hope it isn’t.
Neither of HCS’ parents is particularly thorny, so I’m not sure where it would get this sudden instruction to make all these thorns from.
ALL of the new growth is like this. Here are some pics from this morning showing the thorny canes growing from relatively thornless original canes.
Here you can see the new side shoots are thornier, but also the stipules in the upper left corner, which were already a little fringed before, now have a wildly serrated appearance:
I think it could be a mutation.
There was a potentially mutagenic event here in April, but that’s my farfetched theory.

Smooth buds before ( sorry for the poor pic, it’s a zoom on an old photo, I didn’t take many pictures of the buds before)
Buds now: very glandular and again very very fringed stipules)

Actually, Blue for You is particularly prickly for me. It always has been. An interesting aside… Chrysler Imperial was bred with Virgo, which was considered “thornless” to produce Jadis, which was one of the prickliest roses in my old Newhall garden. Virgo was also bred with Robin Hood to produce the nearly thornless (bush form) Iceberg. Chrysler has a double dose of Charlotte Armstrong in it and that was NOT a particularly smooth parent.

Thank you Kim!
You are right, I just looked at more pictures of BFY on HMF and saw the pictures of very prickly stems posted by you and Marlorena. They look very similar to what I am seeing in HCS now. So I guess it may be reverting to its mother’s thorniness. Mystery solved! Well, I’ll be honest and admit I hope he returns to his original smoother form someday…
Thank you so much for sharing your knowledge!