Germination research (Rosa canina) Seeds


Amazing how the researchers seem to be hesitant of going “just below” zero (-2 to -3C).

Or is it fear of soil ice crystals rupture in or into hardy plant seed covering tissue? Ice crystal growth great for eventually spalling concrete, and rock. That should break the seed “tissue barriers” if required, for germination process to begin as temperature raised and ice melts.

Good experiment in that did two stage thermal change (paper at least they went to 4C). Would of like to see moist control group at 22C + fungicide.

I tend to ignore the chemical additive comparison - prefer physical forces.

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I note that in the final conclusions are stated the need for higher doses of the growth regulators, and a longer stratification period. I understand why higher doses should be investigated, but I’m not sure where the evidence lies to conclude the need for longer than 14 week stratification. Did anybody pick up on that?

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I don’t do rigorous controlled germination experiments to determine a diminishing point of return for life just below zero C period. I just had to figure out a way to get germinations.

However this December year pulled out a couple of trays after ~ 8 weeks at -2 to -4 C of a few hardy crosses (less than 100 seeds). Put on heat mat, moistened, under lights and at 19C in enclosed grow tray. Nada after 2 weeks - back into just below zero cold. Long Target length is ~20 weeks for this year.

Might do intermediate duration in February and leave tray at room temp until June - if no germination back into ground for winter.

This year will be my largest domestic scale, privately funded test of ~ 1500 seeds of 60+ crosses at just below 0C.

Only testing one dominate variable - thermal, and lesser time in my private hypothesis. No chemical variable.

My Longest duration of accidental on purpose thermal cycling was two years of 2020 harvest of species. Inside cold stratifying (~ 35 to 45F) - 3 months - nada, then buried in July 2021 in pots, in ground for full winter of -20 to -35C. Germinated spring 2022 a few varieties from these outside potted in ground seeds (2 year cycle).

Same year spring germinated 2021 seeds inside using just below zero C method - after ~12 weeks. Indoor duds put into ground for this winter. Another 2 year try for batch of life below zero duds.

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Forgot one more minor bubbling test idea for next year’s hip seeds is going to gently nick/burnish seed coating. Will use existing in-house tech…

Done by others so not new but not found post facto germination results. Anybody have any?

Trying to avoid methods hard on the eyes and shaker hand, and faster than 1 1/2 years to 2 years.

Will replace a corn cob polishing media for a spent brass polishing machine with slightly tougher and larger material sized - sized so that seeds pass through a screen but media retained. Should allow mass production of treated seed.

Anybody tried the polishing tech? … Vitamix out even though mine built like T32 - too expensive to bung up.

Purpose, if works to improve germination may reduce time and fuss.

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You’re right. Their experiment did not test different periods of stratification, but there are some references to previous experiments which did. Maybe they were hesitant to simply state higher doses should be tested and concluded upon other earlier research that it would be good to also include a variation in stratification time.

I’ve read and heard that roses from the Caninae benefit from longer stratification periods and in the wild quite often germinate after two winters. I’ve sown some Rosa corymbifera a few years ago, none of them germinated. Threw the seeds under my hedge. Next year found some seedlings. It is said to double the cold stratification time for Caninae seeds (canina, rubiginosa, corymbifera, …) in order to have a higher germination rate. That would be 180 days in stead of 90 days f.i.

I have the impression that they feel their research is a bit incomplete. That they should have gone a little further in their testing.

Wouldn’t this also be an extraction from a larger reference work?

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Ahh. I had not read about the peculiarities of Rosa Canina, but I searched the forum and found where Karl K had posted a study by Rowley several years ago. Unfortunately, that link is dead, so I’m reposting it here. Excellent information.

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Many txs for the two preceding inputs and links in this thread.

Have not read slowly and in detail yet but will - not that long of a read - but in my world this first blush is a very good test paper for hardy rose species seeds and from the 50’s simple research testing to boot.

Few things l have not done … eg care at what time to harvest, sit them for couple months in damp vermic. - mine most few weeks at room temp., but damp.

Verbatim … love it …

“ The pots are then stood in a warm glasshouse for two months and then transferred to a refrigerator at approximately freezing point for a further two months. Care is taken to dampen the vermiculite so that at no time do they dry out completely. Finally the achenes are sifted out and sown in the normal way.

A simpler method, if no refrigerator is available, is to bed the pots in ashes outdoors during the winter. “

Have to read to see at what “approximately freezing temp…” and thermal cycling details.

Go to ice theoretical formation temp ~ - 0.6 / 0.8 C (from non googled bad memory) and get it over with. These are hardy roses and so will their seeds be if they are at theoretical ice formation temp… - wouldn’t make Darwinian sense otherwise.

You can always go warmer - been there, failure made me head to ice for stratification temp. Now it appears from paper, thermal cycling and longer important secondaries.

No chemicals will be used in my learning curve.

Again txs as been a frustrating journey just to “get a germination” at the minimum from hardies.

Well finally found in an ancient “wizened” historical UK “research” paper (1935). Has a strong stratification section on temperature testing on rosa germination for different cold storage duration, H2SO4 treatment, different media (peat moss and acid ph effects etc) between -2C and +2C and +5C.

Other germination topics touched on. In total 18 tests discussed with emphasis on temp…

A very brief pointed conclusion (like the old right way of doing it) - last paragraph page 416-17. Also other workers mentioned Cocker et Barton (+5C).

"… In conclusion, it is definitely established that some acceleration of the germination of rose seeds can be caused by storing the seeds in moist sand or other medium at a cool temperature of —2° C. to 2 * C., or at 5 0 C., or in the soil in autumn and winter.

Low (—2° C. to 2° C.) accompanied by dry conditions do not accelerate germination by shortening the period of after-ripening; moisture is necessary, aeration is also needed."

Reference found from paper link provided by Lee-Hull on this thread

By Dr. M. A. H. Tincker, M.A., Wisley

Journal Of The Royal Horticultural Society Vol-lx (1935)

Done at Wisely (RHS), should of known better that I would find it in their history … hop skip and jump from SIL place. Another pilgrimage place added to this years UK visit agenda.

Impact for me … pickup a few things from both papers to try, but no magic gold standard method.

  1. Staying with low temp end point stratification (just below zero C), indoors, and temp cycles for first 5-7 month after harvest. Then indoor to out door in garden for another 5-7 month real winter thermal conditions (since not a production or commercial op). Outdoors is final stratification stage and allowed to germinate as far as achenest will go within 2 years.

  2. Also more selective and disciplined on hip ripening vs harvest time.

Forgot ….

Quod erat Demonstrandum

… about as good written conclusion for me for documentation of an end of a germination learning journey. Now found to have already been done in neo-classic horticultural science published works, and from reading interpretations of Darwin’s post field trip small musings.

Keep it going Karls someone found your efforts rewarding.

Now for 2022 crossings germination effort monitoring.

The biggest problem I see with this study is the tiny sample size. Any variance in germination due to the treatment protocol is easily overwhelmed - masked - by the occurance of diseased embryos and seeds lacking embryos. Statistically, the difference reported here meaningless.

It would be easy enough, though, for anyone to repeat the experiment in a meaningful way using a much larger number of embryos extracted from their pericarps but left in their testae.

If there are any budding biochemists out there then I would recommend investigating the processes that occur independently in the testae and in the embryos. I think you’ll find that abscissic acid is created from a reservoir of carotenoid precursors in the outer layer of the testae especially near the poles of the embryo in a temperature dependent enzymatic reaction and that abscissic acid is degraded enzymatically in the embryos. Oxygen is involved which is why cold temperatures are so important to the breaking of dormancy. Contrary to the article you will find that testae actively transport oxygen to the embryo and possibly CO2 from the embryo. Microscopic examination of testae show stomata are present on the testae and I’ve seen gas bubbles form on the surface of testae.

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Don, agree good points for budding research scientists to continue to explore for with the improved fundamentals-knowledge and tech … even ~90 years after paper.

If l conclude right, your research lends credence to using very porous media (aeration) as a stratifying bed material. Tried vermiculite, changed to volcano eruption origins, natural pearlite.

As an aside, interesting and comparatively, my old company research group was divided into fundamentals and “practical” scientists and engineering scientist groups answering to their customers who were operations and project development. I was in PD and Projects.

Back to the mission … l chose to accept as a part of a MI singularity.

Still waiting to recognize a robust gold standard for practical applied science advice to use for hardy rose seed germination where in nature plant canes, roots, and seeds exposed to prolonged temps below, to way below zero C. Or better still, practical advice for practical purposes - beside move south to use or West Country Cornwall.

Didn’t get any l recall, except finding practical experiences from Finland and the Prairies. But a lot of good encouragement as in basically “give it a try” (Stefan, and secret Cdn Albertan Rosarian). Nothing to lose justification.

The one commonly cited, or suggested, for stratification (above 0++C) is likely okay for zone 6 and above, and for some transition zone before the 2 3, 4 zones (or vice versa) where very hardy winter species roses, and their seeds historically originated - developed - and flourish (rugosas count both non hardy (hybrids) or hardy species/hybrids).

Don’t know start of, or breath of hypothesized mix transition zone, but l might see it after 2022 seed stratification results - though likely masked by a myriad of variable influences. But it exists because “semi hardy” roses are transitional genetic expressions and reaction to climate factors (imo) - grow bigger and thrive in warmer areas (imo).

However for this recreational gardener, giving up after 3 seasons on standard warm zone method was practical based on time allotted criteria. As was moving way below the lower temperature of the generally accepted status quo paradigm.

No point in dancing above 0C. Just had no personal physical proof, but 0 and 1 germination after three tries not hard to compare to or beat - even by intervention chemicals.

I consider my results statically significant in my world when compared 3 yrs of “0” to “1” germination at warm for hardies dormancy temperatures, to 6 after 1 warm (0) + 1 winter in ground, and 12 after 1 session at 12 weeks below 0C indoors.

The tests are minus student T test analysis or superior, for test sample(s) pop size decision vs CF limits and significance math vetting of results - seeing comparative incremental differences is believing in my world.

Why l went full tilt this year on hybridizing rather than spinning my wheels. Based solely on the two test runs and two different temp cycles (difference ?) and duration at just below zero C for stratification.

The break through for me was just fortuitous luck, and anecdotal info on Percy Wright’s seeds in a can stratification in a snowbank and a Finn’s method of stratifying outside including germination and subsequent gauze tunnel sheltering of seedlings in spring - most detailed public info expertise experience l found available, …. until the 90 year old Wisely Park RHS work.

The luck was my engineering earth science background concerning ground penetrating frost depth and temps the real hardy roses flourish and survive square tire winter temperatures.

This tying of covariant empirical, qualitative and semi quantitative temp data info made the poltergeists of the Big 5 to take physical possession, and place below grade in the garden the last inside batch of 100% warm stratified seeds using the status quo warm method.

They were by July 100% deemed duds by myself. The pots buried and experience a summer second warm cycle, and a first winter at just below 0C temp.

Sometimes 70%-80% of winter time (Nov to early April), some snow cover, 20 - 30% of time bare concrete-like garden soil due to chinook warm winds, and winter period temp range anywhere from +15C to - 35C. (Experienced -40 to up north -44C, scale doesn’t matter - ignition locked when turned to start and blew apart a starter motor on new car)

The dud batch produce 6 germinations the next spring consisting of a mix of hybrids, Canadian Bugnet’s Lac la Nonne rugosa, American Hansen hybrid blanda, Lillian Gibson, a spino species and my personal Butterball (FL Skinner spino hybrid) x something in my cross (in records), and a species altaica.

The seed numbers were never more that 200 in each test of the separate three stratifications above 0C - used pressed formed peat bog harvested containers - banning in UK.

Below 0C tests in recycled plastic 4” x 4” nursery pots - don’t want tannic acid / organic acid derivatives influence claims (except when transferred to outside to in-situ stratification / winter - summer temp cycles).

Last year’s hybridization harvest is1500, +5/-20% seeds and + 60 crosses reconn. survey results (of 128+ made) now being stratified at just below zero C. Any duds will be placed into garden test plot for natural warm and second cold cycle. I need to expand present space in garden.

Some crosses use semi-hardy to non-hardy parents in pair. Single to << dozen seeds found in some of the crosses and they are unlikely to germinate. Probably seed - pollen parent genetics seem not to like their selected arranged mating - all other “things equal”, as in contain all morphological parts of a rose.

In my applied science world of practicality 500-1000 seeds per test is pointless as its a diminishing return approach after 3 consecutive seasons of flops - leave that to funded researchers or commercial entities who might be able to afford undergrads and or field workers,.

You will have noticed in good doctor’s conclusions, the semantics he used … “definitely “some” acceleration”. I view it as qualitative and typical for some conclusions imo for not jarring the status quo method paradigm, and/or he didn’t believe fully in his observations - room for doubt as you mention.

I “feel” the paper’s minor weakness is he eliminated in his count, germinations that were malformed or weird … if he did not do it on a universal basis (control - can’t remember). l would not have done it because no externally added X,Y,Z’s in 17/18 tests except H2SO4 test … just nature germinations of dead ends.

IMO good doctor is “just simply right” in his conclusion as l proved it to myself by using my self-generate horticulture equivalent of rev A (soft Rev) CSTM procedures for hardy rose seeds germination … because it works to give “some” acceleration.

Only question for me is all my warm - cold - warm - cold - warm recycle “cycles” really required ? Probably not. The good doctor’s work implies no. For me, the circumstances of my situation (retired) don’t make the work a burden. Probably continue it for awhile to wring out every last germination possible for a season’s harvest of crossings.

A well respected Canadian rosarian is rumoured to be seeing if my results are repeatable and vs status quo rote method for full hardy species and less hardy crosses (Z234). Way more careful and precise than moi’s techniques and source of the seeds in snowbank stratifying story. This testing is a good thing in the big scheme of forward progress, or reset.

Made in Canada Documented potential applied science option - solution for germinating real hardy crosses might result from borrowing from way up Finland, Wisely work and some of the Prairie. N.A. Big 5 anecdotal experiences … l hope.

Summing up for me, if you can’t get stratification germinations at the suggested status quo temp range of 35 to 45F, turn the dial down a touch or jump to 32F and try. Or plant in ground. I did it both ways and it works.

Only science change l did was a soil component phase change from a liquid to a solid (ice) and kept at “highest” possible “lowest minimum” temp. Not trying salt to go lower - not wise.

If no playing of the temp band works with aerated and moist growing media … crosses maybe problem.

Wow what a lot writing for a common natural climate cycle soil component phase change that was tested. Must of been really PO’d by lack of germinations over 3 years.

Hopefully others wont experience it with rock hardy rose seeds, and if they do they have now two ways out to try, besides the third known as bailing.

One important consideration for most who are starting, for moral and encouragement purposes and as a norm in my experience, is both methods, do not give “big” absolute germination scores vs hoped for expectations prior going into stratification.

My experience has been zero to 12%. Others are higher. I am confident my performance score will greatly improve over the seasons.

“Big” to me is 20%- 40% and suspicious is over 80%, excluding “multiflora derivatives”. I am sure there will be exemptions to my generalization like mentioned.

One way to up score is to selectively cull seeds for doubtful. I don’t, instead l let nature do the natural selection process work for me in case l toss a beaut.

And in continuing with my Big 5 history DNA collection, bringing into my gardens for 2023 Yatkan (sometimes kt reversed), more Isabelle Skinner, Gay Centennial, more Dr FL Skinner, Ross Rambler … Euro Canadian pioneer transmigration roses “Grannies Rose” and my present favourite more “Indian Head” - 80% laugh off a real winter. Who said these roses don’t sell ??? Not me.

More tech on newer existing past germination work l missed that hits it imo … to be posted … to come from a neutral party. Wow its gold - should be read.

Got find that imported new Opinel pruning knife and re - gift … twice to the same person … still haven’t delivered first.

Loss leaders pulled out today from below of 0 C 1 week before end of 90 days incubation. Random late season crosses.

Point of photos ? Visual doc of “ice” on rosey pond.

Green moss pearlite ones pulled at Xmas for trial germination of 14 days after 60 days below 0 C

![image|375x500](upload://AqlOsEyM0oXQPAPj0rSp4YAPptf.jpeg) ![image|375x500](upload://ubuAP2DJbpyuAaBZd3oLDT6OkHK.jpeg)
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@RikuHelin I wish I could see your pictures but they are not showing for me. Perhaps broken link?
Edit: I noticed there’s an exclamation mark before the first bracket and another one in between your links… maybe that’s what broke them. Perhaps if you reupload it will work.

Hi SeasideRooftop

I have got a request in for help as not sure what l am doing wrong - “photo loading use to work for me - might be an age thing ” — trying to make it work leading to me using lots of “correction” notices … thought l had new software down

I’m not sure what the problem is… From my end I can see extra exclamation marks in your links to the photos. Perhaps those exclamation marks were meant to be at the end of your paragraph but somehow ended up in the part of your message where the photo links are.
Perhaps try just posting the pictures , with no text, in a new message?

Hi SeasideRooftop

I am using iphone 14 photos lib option.

Straight copy using apple command will not paste onto conversation “reply”.

Previous way that worked was on iphone forum reply screen go to bottom right photo icon. Click, asks which option, click photolib comes up with my iphone pics as mosaic, tick photo want, click add, churns away on the app with dumping of code onto conversation window, when hits 100% uploaded flash error but no reason.

Apple Iphone released iOS 16.3 today downloading to see if eliminates prob.

Edit used same old method and finally got both pictures wanted 5 edits ago.

The silver pans are to contain the water as ice melts and drains through pearlite over soil and out a hole l poked in bottom of red cups. Large silver only tray for large number of Auli OP seeds harvested properly (Finn gallic - not rock hardy but good bloom form and clear pink) . No drains for ice melt.

Red cups drain into pan to keep seeds pearlite over “earth moist” like a flower pot. Actually about 1/8 in pan water depth few hours after pulling from fridge. These are likely low prob germination cups as crossed and harvested late in season. Only semi hardy to tender crosses but given same just below zero C treatment.

Also stuck in January harvested seeds from hips of “red single - semi hardy - tag lost” x fedtschenkoana (hardy). Already been cold treated outside but not harvested before today - (apparently negative approach vs readings)

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