R. arkansana two

General Discussion
1

Continued from before:

I didn’t try R. arkansana as a female before this year and am excited to see hips forming on it from crosses to a wide array of modern roses. Hopefully there’ll be seeds inside and viable seedlings! THat one seedling also is setting hips well and hips are forming when it is used as a male.A friend had some R. arkansana plants she has worked with that were disease susceptible and she gave up on them. She also rarely uses the Morden series of roses in breeding too because they tend to be more disease susceptible in the Twin Cities than say the Explorer series. I wonder if up in the Northern prairies where it is drier if the R. arkansana just weren’t selected strongly for disease resistance. Maybe this one from Morris is a good selection because Morris isn’t as far into prairie land and the potential for higher humidities may have helped select for disease resistance in that population compared to some Canadian populations used. I am excited to see what next years seedlings will bring!

I’d love to learn about others experiences with R. arkansana.

Sincerely,

David

2

Wow, congratulations! Looks like you found one nice rose.

Joan

3

I’ve got two hips maturing as we speak on an arkansana from carolina pollen. I haven’t tried to do much with this plant because it tends to get mildew and it doesn’t rebloom as I had hoped it would. It is very healthy otherwise, and is threatening to take over the backyard at my parent’s house (sending up suckers up to 10 feet away from the original). By the way, the reverse cross, is also forming seeds. This adds the arkansana to the very short list of pollen parents that have been successful on my carolina. One reason, I used the arkansana at all this year, was because it has yellowy-orange petals at the bud stage. I was thinking maybe this yellow-ness would be helpful in getting anything other than just pink into future hybrids (ones with a heavy background of N.A. native species).

4

My clone of R. arkansana came from Cheryl Netter in Colorado. I haven’t bred with it because it is susceptible to rust here. It is encouraging to hear that some species clones are more fertile than others.

The R. californica clone that I’ve used in the past was selected because its flowers were larger and more deeply colored than other clones. It has given me no seedlings as a seed parent, and few seedlings as a pollen parent. This year I used pollen from a variety of R. californica clones, and appear to be getting better hip set than in the past, particularly with pollen from the clone ‘SMCN’ (San Miguel Canyon - North). Next year, I’ll try SMCN and some of the other clones as seed parents. In the wild, SMCN sets more hips and has more seeds per hip than other R. californica clones.

5

I have only done a bit of work with R. arkansana. At first, I found it difficult to obtain. I now have it from 4 sources that have bloomed:

White Rabbit Roses clone: this is the best, a strong, solid medium pink, and very strongly recurrent, sometimes making me think of a floribunda. It is only a bit over 1 foot high, and shows no tendency to sucker so far. I tried a few crosses onto it last year and was surprised to see a couple of them make seed. No germination yet. I have used its pollen for two years, but it rarely takes. All of the handful of seedlings big enough to plant out are the same cross, from both years: ‘Sequoia Gold’ x R. arkansana. SG is an exceptional female parent, although its small seeds have high mortality when sprouting. All of these seedlings are very dwarf (maybe too much so to be fertile?) and haven’t bloomed yet. Some OP seeds from this R. arkansana clone that I sowed a couple of years ago gave me several seedlings, all apparently pure R. arkansana. Interestingly, they haven’t bloomed yet.

I also got two plants from Forevergreen Farms. They obviously are seedlings, as one is light pink and fairly solid, while the other is slightly darker and distinctly marbled. They are otherwise similar: tall for the species (2 feet), and very shy bloomers with no recurrence. I have had very, very few seeds from their pollen, and no seedlings yet.

I also grew this species from two seed sources in Canada: My friend, Jim Sullivan in Saskatoon, and the Devonian Gardens. These are all very short (6-8 inches or less), and very light pink, almost white. No recurrence yet, and I haven’t tried to breed with them at all.

David, I read in one of my flora books from your area that the populations of R. arkansana on the eastern edge of the plains are hybridized to a greater or lesser degree with R. carolina, forming a fairly smooth transition from pure forms of one to the other.

I read that the Canadian hybridizers found crosses with this species very difficult to produce, which is presumably the reason that they used only a few such foundation hybrids in their work to produce the Morden roses.

6

Roger,

“…populations of R. arkansana on the eastern edge of the plains are hybridized to a greater or lesser degree with R. carolina, forming a fairly smooth transition from pure forms of one to the other…”

I guess that would help explain why these two species, which have been reluctant to cross with much else for me, have turned out to be so interfertile. (I have hips from both directions of the cross, maturing right now.)

Also, thanks for the O.P. White Rabbit Roses clone seeds, I’ve gotten two seedlings already. And I’m glad to read that the parent is so recurrent. I hope the seedlings follow in those footsteps.

7

I was always puzzled by an old article in the ARS yearbook about NA (North American) x NA hybrids, since they had such unexpected results, particularly regarding the fertility of the F1 hybrids. I won’t “name names” since I don’t have the article with me, but she got some quite sterile F1 hybrids in cases where the parent species are reported to interbreed freely.

When I have bred with the NA species, the variability in fertility (relative to producing the F1 hybrids in the first place) within a species has been remarkable. I now think the problem is that these species are highly variable, even when they may look the same. R. carolina and R. arkansana may indeed be fully inter-fertile in Iowa and Minnesota, while clones of the same species from elsewhere might behave the opposite way. I increasingly think that the NA rose species (at least east of the Rockies) are the “black pit” of rose taxonomy. David Z. and I have discussed plants of R. virginiana that he has seen in Wisconsin and Minnesota, but my Michigan flora (by Voss, who actually seems to know his wild roses), swears that R. virginiana is not found in Michigan, let alone further west, and what we have is actually R. carolina. Checking a very professionally-done flora of Minnesota yielded the rather astonishing statement that there isn’t even any R. carolina in Minnesota and R. arkansana is the only native tetraploid. I suspect that these three species are only partially distinct and the Minnesota book may have been using a different definition than I would. I have seen some very strict ones that would leave a lot of roses I grow with no name what so ever. My local native tetraploid has too many internodal thorns, and is too short, to be the classic R. carolina, although I am sure that is what it is. The NA clone that I use the most for breeding, R. virginiana ‘Harvest Song’ (from Heirloom Roses, not to be confused the hybrid rose by the same name), fits the classic definition of R. virginiana (partly shiny leaves, longer, straighter thorns), except that it has glandular hairs on the hip. This is a R. carolina trait, according to some. I guess the real answer is: collect nice roses, try them out as parents, don’t worry too much what they are!

8

I’ve been trying to root cuttings of this stippled R. arkansana and the hybrid of it to no avail. I can usually get cuttings to root pretty well. The leaves hang on for awhile and then yellow and fall and then the stems eventually die. Has someone worked with R. arkansana and have some suggestions? Maybe I’ll need to graft these plants or wait until they send up suckers. The Morden roses that have R. arkansana in them seem to root pretty well from what is written about them. Maybe they are removed enough from the species.

Sincerely,

David

9

Have you tried air layering?

10

Interestingly, Percy Wright when he crossed Rosa rugosa (probably ‘Hansa’) with Rosa arkansana, even though the progeny theoretically would be triploids some of them had good fertility. Because of its drought resistance and ability to bloom on new wood, it should be hybridized more with other hardy species that repeat their bloom and then used in a breeding program. Rosa laxa, etc.

If anyone wants Rosa arkansana pollen from selections with deep pink flowers next summer, contact me. At this point you will have to write me at Box 1907, Edmonton, Alberta, T5J 2P3.

Paul G. Olsen