Lots of newbie questions about Open Pollination

Hi everyone,
Over the last few weeks I’ve been wondering about open pollination, so I am making a post with all my questions, hoping they’re not too silly. I would love to know what the experiences have been like for you all.
I have a few roses that set OP hips that I really didn’t plan for in my project for this year. So far I’ve let them ripen bur don’t know how to evaluate whether they’re worth keeping or not.

  1. How do you decide whether to keep OP hips or not ?
  2. Is there any kind of science or even empirical observations you have made about the odds of selfing vs getting pollinated by another rose’s pollen ? Does the class of the rose, or petal count, affect the odds?
  3. How far can pollen travel? In my small garden, I wouldn’t think a rose that’s right next to the OP seed parent is that much more likely to be the pollen parent than one that is five or ten meters away, or is it?
  4. Could bees etc carry viable pollen from roses in another garden in the city? This would add a whole new degree of randomness to the pollination.
  5. Why is it that OP hips seem to be bigger than the ones from my intentional crosses? I’ve struggled to get Eyes for You to finally form three tiny hips, but while deadheading her other blooms I noticed they were forming hips that were younger, but already bigger than those from my crosses! Why is that?
    FYI the other OP hips are on Iceberg, “Comte de Chambord”, Honorine de Brabant,The Lark Ascending, and Royal Jubilee, but I don’t mean to limit my questions to these varieties at all.
    Curious to read any feedback on this topic!
  1. How do you decide whether to keep OP hips or not ?

Is there anything about the parent you find intriguing? Is the variety particularly good, healthy or attractive where you are? Would raising its seed assist you in learning how to germinate seedlings or answer your questions about whether it may be one you might consider using for a seed parent?

  1. Is there any kind of science or even empirical observations you have made about the odds of selfing vs getting pollinated by another rose’s pollen ? Does the class of the rose, or petal count, affect the odds?

Ralph Moore stated repeatedly over the years that he never found any evidence of cross pollination. He felt all self-set hips (or OP hips) he raised were self set due to the stamen folding over the stigma and shedding pollen on itself. Then, I raised OP seed from Stellata mirifica (a RARE occurrence in my garden) the plant set as it died on me. Two seedlings resulted and neither of them appeared to be solely Stellata. They did, however resemble the rose closest to mirifica on the hill…Fedtschenkoana. The remaining seedling I’ve called “Puzzlement”. https://www.helpmefind.com/gardening/l.php?l=2.69411 I would think that fertility of the type and petal count would be the greatest factors affecting the odds. Roses with low fertility aren’t going to set many hips with any pollen. Extremely double flowers are less likely to set seed due to the petals shielding the stigma.

  1. Could bees etc carry viable pollen from roses in another garden in the city? This would add a whole new degree of randomness to the pollination.

Why couldn’t they?

  1. Why is it that OP hips seem to be bigger than the ones from my intentional crosses? I’ve struggled to get Eyes for You to finally form three tiny hips, but while deadheading her other blooms I noticed they were forming hips that were younger, but already bigger than those from my crosses! Why is that?

Perhaps it’s due to the amount of pollen being applied? Are you applying enough pollen compared to what the plant floods itself with? Ralph Moore theorized he might not have applied enough pollen to result in successes he wasn’t achieving so he tried reapplying pollen to the same blooms for several days in succession with a bit greater success. Eyes may be smothering itself in pollen over the period it may be more fertile while you aren’t applying enough or at the wrong time. Or, perhaps the mate you’ve chosen for Eyes isn’t as compatible with it, or the pollen you’re using isn’t very fertile?

  1. Available space. If the seed parent has any specific trait I’m after or likely has it as a recessive (eg I plant out Ann Endt OP seedlings often, it’s not uncommon to get thornless seedlings from it, likely due to the foliolosa genes).

  2. It’s going to vary depending on what’s used. Some species seem to be preferential outcrossers. For example, I’ve never had Bracteata seedlings survive that aren’t obvious crosses with rugosa, bracteata never set many hips until this year (likely because Clinophylla is in my garden now and they are closely related and likely very compatible).

The more double the flower is the less likely insect pollinators will visit it (or succeed in getting to the relevant parts).

I have the hulthemia eye turn up sometimes in OP hips. Unless there’s a distinctive trait or obvious species influence it’s probably hard to tell though.


3. I think someone on here mentioned that rose pollen is “heavy” so doesn’t wind pollinate much/far but I may be confusing it with something else

  1. Eyes for You seems to be an iffy hip parent. Some people get it to set hips relatively easily, others struggle. I’ve had it for 4 (maybe more) years and I only got 2 or 3 small hips on it this year despite trying in previous years. Even on the forums here there’s posts by people talking about how it would drop it’s hips early and such. It may not be the best indicator of you doing something right/wrong.
  1. How do you decide whether to keep OP hips or not ?

Maybe you want to obtain a repeating rose from a non-repeating rose that was made from a non-repeater x repeater. That is something I’ve been thinking about lately. Why OP would be usefull.
I’ve had some OP, but I’m not that keen on them. Until now mine were all selfs, resembling their parent almost entirely. I cull them quite easily and only keep the ones that are strongest and defer more from their parent, all be it not that much.

  1. Is there any kind of science or even empirical observations you have made about the odds of selfing vs getting pollinated by another rose’s pollen ? Does the class of the rose, or petal count, affect the odds?

I’ve got some roses that haven’t any stamens, like Charles de Mills for instance. This year I left all flowers on the bush and I think I’m getting two or three hips. Not sure yet. But these should be pollinated with pollen from other roses. Another explanation could be that Charles de Mills occasionaly does make stamen, and that those hips will be selfs.

  1. How far can pollen travel? In my small garden, I wouldn’t think a rose that’s right next to the OP seed parent is that much more likely to be the pollen parent than one that is five or ten meters away, or is it?
  2. Could bees etc carry viable pollen from roses in another garden in the city? This would add a whole new degree of randomness to the pollination.

Honey bees travel from 3 to 5 km (I’m Belgian, I use metric system, sorry about that :slight_smile: ). But honey bees mostly tend to work on the same type of flowers and then switch to another when they’re done, starting with the nearest and most plentiful type of flower and working their way outwards. I think you’re more likely to get pollinations from roses nearby, if it would occur. Bumblebees and wild bees are perhaps more chaotic, but still, they won’t fly long distances if there are flowers nearer.


5. Why is it that OP hips seem to be bigger than the ones from my intentional crosses? I’ve struggled to get Eyes for You to finally form three tiny hips, but while deadheading her other blooms I noticed they were forming hips that were younger, but already bigger than those from my crosses! Why is that?

I’ve noticed this also. I think they’re more compatible and maybe that gives larger and more seeds. But the suggestion of Kim, that it could be due to more pollen is also a likely explanation.

Thank you for your replies Roseseek, Plazbo and Karelbvn!
Your experiences regarding the selfing or not question are very interesting. Great to read about Ralph Moore’s beliefs regarding this, and to see that Karel’s experience is similar! I too had wondered whether the stamens folding over would just trump everything else. So I was fascinated to read Plazbo’s comment that some roses didn’t set any OP hips until another rose of a compatible type was added to the garden. I guess I had also underestimated the question of self-incompatibility in some varieties. I’ll need to look into that to understand it better.

I read in other threads here that Honorine de Brabant can pass on its stripes, so I’m going to keep those and see if there’s any decent striped offspring. I might also keep the Lark Ascending, just because it doesn’t have any recorded descendants on HMF and I’m curious.
But the space issue is a real limiting factor. At this point I’m almost hoping for low germination rates on some of these. I’ll need to be more reasonable in the future… Or find a neighbor/friend willing to host a pot ghetto of my seedlings!

Karelbvn, that is really interesting about the distance bees can travel! I guess there’s really no way to know for sure what the bees will do. I have no problem with metric, being European too. What I don’t understand (and maybe there’s no answer to this) is the definition of “nearby”: if a rose is right next to another rose, is it more likely to be a pollen parent than another “nearby” rose five meters away? My garden is small, about 80m². Would all the roses in the garden be considered as “nearby” or only the very closest neighbors ?

Regarding the OP hip size, I guess sheer amount of pollen is the reason. I did pollinate each flower several times, not just EfY but all my seed parents, at least two days in a row, sometimes three.
But maybe I wasn’t using enough pollen each time. Thanks for the advice on that, Roseseek ! I’ll gather much more in any future attempts.

You’re welcome! If possible, just gather a PILE of it to use, then smother all the seed parents with it. I literally gather everything available from specific pollen parents and just keep adding it to the pile to dry.
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Wow! That’s a lot of pollen Roseseek !
And here I was thinking I had a lot when I 'd only gathered it from two or three roses… Thank you for sharing that pic, I need to scale up my pollen gathering efforts!

You should! Getting anything out of Banksia lutescens requires an unlimited supply. I had two 8.5" X 11" sheets of paper covered with their drying material.

Interesting thread. All my roses have plenty of hips, but I haven’t noticed pollinators being especially interested in roses. All the pollinators are very picky and know what flowers they have come for and which they prefer. Maybe they like the small, single roses on Rosa chinensis “Angel Wings”. Maybe I just don’t pay enough attention to watching what the pollinators do.