Rosa primula is diploid (12). Does this affect which rose pollen it accepts to make fertile seeds?
I’ve been trying to hybridize with R. primula for years. Please help!
Thank you.
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Welcome! Not necessarily. Skinner released “Karen” in 1964, reportedly a cross between Primula and Spinosissima. That’s diploid X tetraploid. 'Karen' Rose My experience is Primula can be “miffy”, but I also keep trying. Good luck!
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Unfortunately l have never tried it as a seed parent because my version from Pickering doesn’t set hips. Contra to Karen’s existence.
Have tried it as a pollen parent in my early days but no progress to report of use to you.
Had it about 10-15 years. Like the rose (prickles’ form, color of new prickles and “ferny leaves”). It occupies a prominent place in the garden.
But with my soil it tends to get chlorosis (at least thats what l call the massive yellowing of the leaves). Doing it now after breaking dormancy.
Some rugosas also do yellow in my garden.
Have to give it an iron fixes every few years multiple times and it clears up. Reminds better do it soon.
Might want to try a reverse cross with it as a pollen parent … if not already tried.
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Many thanks Riku! I appreciate your perspective. I also love this Rose because of incense.
I’ve also tried it as pollen parent and will continue trying.
Can you educate me? Does pollen remain viable? How long? Should the pollen be frozen? I have some containers of Count of Chambord pollen that I want to place on Rosa primula.
Thank you!
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Hello, Roseseek and thanks for the welcome. 
Correction: I see that Rosa primula is 14 not 12 for ploidy.
And thanks for telling me about Karen. I have grown Rosa primula for 30 years, obtaining it from Pickering or wherever else I could find it. Very rare in commerce. It is different from any of the other varieties like hugonis, cantabrigiensis or xanthina.
The one time I got a rosehip from primula I saw one seedling germinate in our cold sunroom, but the seedling died.
The mother plant did very well in Kansas, growing 6 to 8 ft tall and 5 ft wide.
Now living in Minnesota, I settled my plant of Rosa primula in the sheltered garden of a friend, in hopes it would live through the winter (I have only pots). We had a brutal winter and Long Cold spring but it did live through the winter and has flowered.
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I do store frozen pollen, have used it (spinos) but unfortunately not very disciplined in record keeping to tell which ones off the seat of my pants (until it germinates).
But usually store my early pollens (spino) in freezer to dab on summer bloomers after thawing for a few hours. After a year tend not to use it as fresh is usually available. Trying to increase hardiness. Summer pollen has also been stored for next spring to dab on spinos.
Lets put it this way, imo if you have CC pollen available now at room temp, then l would be inclined to at least put in the refrig part now if you plan to use this spring.
My CC did not survive more than a couple of winters protected but most Euro OGRs don’t for me ( in my zone 4a prairie - Rocky foothills climate). Be nice to see a cross occur with R. primula. Good luck.
Pollen tends to mould when at room temp for a protracted time. At least mine did when left between pollination binges at summer garage temps…
Not succeeded with the spino’s unless porsiiini kauntor is one (dabbed on gallica) … info sparse (Finn species). Not densely prickled like my “ Cdn” ones.
I imagine you may have already checked Minnesota arboretums rose inventory?
There is a contributor ex of the cold north - think Minnesota - who is very experienced in trying things you would like to try - deep knowledge base like roseek… Might show up as well as the Dr… from as cold a place.
Btw if you have deep snow cover it works for you in protecting marginals, mine can be very sparse and patchy with a few big falls. Spinos and their hybrids love it here, so much the big comes to mind … but tough for me to cross and germinate even though produce viable seed.
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Riku, Big thanks! I will take into consideration your experience. Where are you exactly? I am in Southeast Minnesota. We had terribly cold weather interspersed with warm spells in January, February, March. It was death to many roses.
Right now I have 11 seedlings. Four are from a hedge Rose growing in the Glasgow Botanical Garden collected June 2023. That Garden was a shambles! Not labeled at all, and somebody pruned the bushes with a chainsaw.
Nevertheless, I have four seedlings. Then I have two seedlings from San Francisco, and orange red shrub Rose. Looks like hybrid tea seedlings to me.
The rest of my seedlings are from about 300 seeds I had collected over the years, I have labeled them jewelry box roses. I’ll have to see them flower and see what I’ve got.
One 2-year-old seedling from Estonia( pix below) looks like a spinosisima variety. I’m waiting for its 1st flower, there are 4 buds. Its foliage is not scented like primula. Can’t wait to see it. Stems red.
With your experience of spinosissimas, can you identify it?
Please tell me how to contact the person you’re referencing who is experienced in Minnesota.
Yes, I will continue to put Rosa primula pollen onto everything I can think of. Hope springs eternal!
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Hi, l am in the province Alberta, Canada. Short periods of night time lows of -30 to -35 C nothing unusual. A few nights of -40C will occur infrequently.
Then episodes of warn Chinook winds, snow gone, and temperature change can be drastic for week or more before plunging back down.
Unfortunately l would not be able to ID that as definitely a spinossissima. Only thing l notice slightly different from mine ( might be photo or my eyes or age of bud) is that it seems to have a less pronounced ovary form at the base of the bud before the peduncle.
Any chance that rose is a burnet or Scot rose? I ask as its structure / form / prickles bear somewhat of a resemblance.
Note : A Scots Rose / Burnet roses are grouped in with “spinossissimas” ( is considered as such). I grow a couple e.g. William’s Double Yellow, Single White Burnet.
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Sourcing material from known Pickering plants is, I think, probably wise. Pickering virus indexed every rose they offered so you know they began as “virus free”. A friend in Texas purchased her Primula from Pickering years ago. I obtained bud wood from hers and budded it on virus indexed root stock. Ironically, Primula is supposedly able to generate extra petaloids. The Pickering originated plant only produces five petals. A self seedling I raised from it throws the extra petaloids. My goal is to raise double forms as I’ve succeeded with Hugonis.
I harvested much pollen from the seedling and have pollinated many of its flowers with Teas and minis in hopes of something succeeding. This is the best result from Hugonis so far. '1-72-1Hugonis flore plena' Rose I love how easily removing the prickles has been with Hugonis. Hopefully, Primula will follow suit.
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Here is my R primula today with buds (just noticed) on old wood. Note the golden hue of the leaves.
I enjoy the prickles’ translucent red color on new wood (be happier to call them thorns for this rose).
And it was socked ( soil drenched to vendor code) with chelated iron solution later in day. It will take awhile ( couple weeks) before turning green with repeat drenching.
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I would also second recommendations to freeze and save the pollen (divide into multiple, smaller batches if possible) for later use, considering the differences in flowering time, among other things. Given the potentially lower odds of success, you should certainly try making any reasonable-sounding cross that strikes your fancy in any direction. With ‘Comte de Chambord’, you might have little choice to but to attempt using R. primula as the seed parent. If you can get R. primula to accept any foreign pollen, then crossing it with roses like the tetraploid ‘Comte de Chambord’ might not be completely out of the question (even though it is still a wide cross with potentially low chances of succeeding). The reverse cross for that particular pairing would be even more difficult because of CdC’s reluctance to produce seed, not to mention its higher chromosome number. The closest thing to CdC that you could use that would be a more reliable seed producer is the David Austin rose Gertrude Jekyll (a rare offspring of CdC), although in my limited experience with it, GJ seeds seem to like to wait two years in cold stratification before finally germinating. If you make that sort of cross using R. primula as the pollen parent (GJ is also probably tetraploid), you might sacrifice seed yield, but would instead favor a smaller number of successful takes from pollen that contains unreduced gametes (in other words, that small amount of unreduced pollen will behave like pollen from a tetraploid rose instead of pollen from a diploid)
Rosa primula is very cold-hardy, so a sheltered garden should be unnecessary in southeastern MN, but it is prone to sudden dieback and death in humid eastern climates in my experience–even though it might remain healthy and vigorous until that point. Keep on raising open-pollinated seedlings if you can to help ensure against loss. As you’ve mentioned, it’s all but impossible to find Rosa primula for sale in the U.S. now, owing to the need to propagate by grafting and the practically nonexistent sales interest here.
I grew a clone from Hortico that had a very strong foliage scent, but compared to the parent, none of its self-pollinated seedlings had more than mildly scented leaves. From that experience, I deduce that there there might be challenges when it comes to inheriting the incense-scented foliage trait. I’ve never tried using it in deliberate crosses, but I have wondered before about the possibility of crossing t with other scented-foliage species like Rosa rubiginosa (which has a higher chromosome count but has unbalanced Caninae meiosis, so its pollen also only has a single set of chromosomes, just like any other diploid rose would.)
Riku, I wonder if your plant’s iron addiction is due to Pickering’s use of R. multiflora rootstock–I would think that R. primula itself might not mind your soil. If you ever do get any seeds to set, any resulting seedlings might not have that same problem.
Stefan
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Speaking of Karen, would you happen to know if it had foliage fragrance?
The only “primula” here (australia) is a mislabel without foliage fragrance, there is reference to a primula/spino hybrid (but who know’s if that’s accurate) which is probably what’s going around down here…it sets seeds so fingers crossed some of those germinate and can be backcrossed and maybe something with the desired trait appears in that hybrid swarm
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Unfortunately, there is no mention of foliage scent on HMF.
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i had about 15% germination on gertrude jekyll hips from last year, and have a couple seedlings still. kept them in the fridge in the hips for 2-3 months.
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Very helpful, Stefan! I have much R. rubinigosa pollen. I’ll watch, here, listen and learn.
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Very hopeful, j.m.! I didn’t know Gertrude Jekyll was offspring of Comte de Chambord. HelpMeFind says it was a “found” offspring. Did they test GJ and find a line to CdeC? Thanks
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Gertrude Jekyll was reported by its breeder to be from a cross between either Wife of Bath or an unnamed seedling and Comte de Chambord, so the latter is its only consistently reported parent. I don’t know if the parentage has been verified independently, but involvement by CdC (at least, what we grow under that name today) seems plausible based on its features. The association with a found rose actually pertains to “Van Doussa Children,” a rose that was found growing in Australia without a known identity and assigned that study name. Its true identity as Gertrude Jekyll has been somewhat controversial, I believe, but here in the U.S. we’ll probably never have to worry about that!
If you have access to R. rubiginosa itself, you could also try pollinating it with R. primula pollen. If the species are compatible, the chromosome number difference won’t be a factor because of the unique Caninae meiosis. The practical upshot of that is you’ll probably have a much easier time getting large numbers of R. rubiginosa seeds and germinating them than you would with R. primula!
MidAtlas, this is very helpful.
Thank you, and thanks for clarifying what happened with Comte de Chambord. I’ve grown it for decades; in Kansas then in Iowa. It’s easily the most fragrant roses in my garden. I’ve collected its pollen over many years, putting it on many crosses, hoping for offspring.
I’ll try R. primula pollen on R. rubiginosa this weekend. I’d like to get a grip on what you mean by the Caninae meiosis. Can you suggest some reading?
Thanks again,
Rachael
Correction: You clarified what happened with Gertrude Jekyll. RH.
There’s a nice, succinct summary of it starting with paragraph 4 in the Introduction section of this article:
You’ll also find plenty of discussions about it here on the forum by searching. As far as I know, the type of unbalanced meiosis found consistently in Section Caninae in this genus is still considered to be unique in the plant kingdom. In all other plants, essentially all of the chromosomes pair up and experience crossing over during meiosis, so that you end up with all gamete cells containing exactly half of the parental chromosomes and a shuffling of the genetic deck, with relatively few exceptions. However, in roses like R. canina, R. glauca, R. pomifera, and R. rubiginosa, only the pollen contains a haploid gamete with chromosomes that underwent a similar process; the egg cell instead contains chromosomes that sat the process out and are essentially passed directly from the seed parent to its offspring unchanged. This means that a substantial number of genes are cloned from each seed parent to its seedling, and only the single set of chromosomes found in the pollen contribute to seedling variation.
The ploidy of the species in this section varies somewhat, but the process is the same regardless. The species themselves act as though they are diploids when it comes to pollination.
However, when these roses are crossed with species and hybrids outside of Sect. Caninae, over at most a few generations, the unbalanced meiosis apparently breaks down. Hybrids like this have existed for a long time; alba roses originated from hybridization between R. canina (a pentaploid) and R. ×damascena, which is tetraploid. The resulting hybrid was hexaploid because R. canina contributed its four sets of unchanged maternal chromosomes via the egg and R. ×damascena contributed its two sets of chromosomes via the pollen.
Stefan
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