Bill, are your seeds still in the fridge? Most of my crosses don’t start to germinate until I take the seeds out of the fridge.
Thanks for all the suggestions and input. Since my last post about a dozen of my crosses have germinated! It appears they took about 90 days to germinate.
Paul, I will follow your suggestion and dedicate certain plants to just seed bearing bushes.
Jeff, Robert, et al, Hopefully, more seeds will be produced and more seeds will germinate as the plants get older.
Jim Sproul, “Bill were your op seeds and crosses colleted from plants treate the same way/” No, most of my op seeds either came from the EarthKind test gardens in Farmers Branch, Tx or from the AARS trial gardens co located with the EK gardens. My roses are all grown in large pots and are fert and sprayed very regularly. Hip maturity was an issue with my plants. Like I said earlier, if a hip stayed on the bush 100 days it was an exception. I’m hoping that as the bushes age this statistic will improve.
Michelle, I had entered some post earlier in the Fall commenting that my hips were not changing color. None of mine really changed color to any extent. Maybe a little dash of light red up one side but again nothing compared to what you would expect. Hopefully, as the plants age, the hips will stay on longer than 100 days and the hips will change color more significantly. Next year I will do a much better job of record keeping!
Jim Tuner, ‘are your seeds still in the frig? Most of my crosses don’t germinate until I take them out of the fridge.’ Yes, they are still in the frig. They went into refrigeration about early oct. Dec 24 I took them out for one week and then put them back in the frig. I did not check them until jan 11 and a large number of op seeds had germinated and a dozed or so of my crosses had also germ.
JIm, how long do you refrigerate your hips and do you just plant them after the time period in the fridge even though none have germinated yet?
Again, thanks to everyone that participated in this post. I have learned a lot and gained some confidence.
bill cashin
While I think it is fine to use whatever technique works for each person, I do wish I could encourage people to plant their seeds in soil once stratification is complete. It is my experience that you will lose many seedlings from transplant shock if you permit them to germinate in the fridge and then try to acclimatize them to soil. I find it is far better for the seedlings to allow them to start life in the soil they are expected to live in. But do what works for you, of course.
The idea of comparing germination rates between known uninfected plants of a variety to those of the same, known infected one would make an interesting study. I submit, though, it is likely to only be valid for that variety. Each seems to react differently to infection depending upon its genetics. Autumn, from what I’ve seen, is all virused, though the infection doesn’t seem to inhibit that rose’s vigor, at least in the gardens in which I’ve observed and grown it in. Many others are runts, damned because of the inhibition infection afflicts them with. It would seem logical that any effects of germination due to infection should be as variable.
Most years, I held my seed in refrigeration until I could plant and conditions were suitable. I didn’t this year and nearly everything is popping up like Winter Rye! Even the odd crosses which aren’t usually this responsive are impressing me. I had quite a few which germinated in the bags, and all were difficult to remove without damaging them. I lost a few, but, fortunately, it was cool and misty when I moved them to soil and most have survived. I’m having more difficulty with the intensity of the sun frying the seedlings at the second and third set of leaves stage, even when covered with screen. The most susceptible in the box are those from Queen Elizabeth X (Golden Angel X R. Californica nana). Those on either side of these three rows are growing fine without any signs of cooking. I know, why QE? I had extra pollen and it was THERE.
Kim I would expect that it would also depend on which virus of the RMV group the plant had. Also, on which strain of the particular virus (there are weaker and stronger strains). Also, whether the rose was being grown in a hot or cool climate as the rose virus immune system works better at higher temperatures.
Hi Henry, agreed. The proposal is an interesting one. It just doesn’t go far enough, nor is it one which would easily extrapolate across the board.
I do wish I could encourage people to plant their seeds in soil once stratification is complete<<<<<<<<
Paul,
What time do you suggest is the “adequate minimum time” for cold stratification in the fridge?
George,
It has been shown that , not surprisingly, many tropical species do not need stratification at all. I know people who have germinated seeds from Chinas and Teas without any cold stratification. It is also known that the seeds of many species, like the once blooming European roses, are unlikely to germinate if they do not receive cold stratification. (I found that R. glauca seed germinated best if it is frozen repeatedly over a period of several months, just as one example) Our modern hybrids are descended from both types and so it is reasonable to expect that the ideal stratification period for any given hybrid will vary. It is a general rule that a minimum of 10 weeks of cold stratification is what roses need. That is the figure upon which my own process hangs, give or take a week this way or that.
To be specific: I start gathering seed hips in early October in some instances, as some of the greenhouse grown plants start into growth about a month ahead of outdoor plants. Pollination starts in the greenhouses in early April for some varieties, so it is these hips that are usually collected in early October. Seeds are collected as they ripen, often as late as early December. (In my climate, roses often continue to grow well into early December before a hard frost stops things) All collected hips are left in a cool part of the house (at room temperature) until late November/early December, regardless of the collection date, and then placed in the fridge.
I start removing seeds from the hips (cleaning the seeds) in early January. Seeds remain in the fridge until late February and then are sown in flats.* The flats are kept in an unheated greenhouse where day temps rise to between 45 and 75F during the day and as low as 28F at night. If night temps are expected to go lower than 28F, the flats are moved onto heating pads that are just warm enough to prevent the soil from freezing hard. (I found light frosts that resulted in the top 1/4" of soil crystallizing slightly was not detrimental to germination)
So, seeds placed in the fridge on Dec 1 (arbitrary date selected) and removed February 14th (also arbitrary) will have been in an environment where the temperature remained at a consistent 35F (give or take a degree) for ten weeks. Once planted out in the greenhouse, night time lows will continue to add to the cumulative stratification effect. However, the swings between daytime highs and nighttime lows are, I believe, just as essential to healthy seed germination of most roses as the cold period is. I have had many a rose breeder tell me that some crosses can sit in the fridge for months and months without a single seed germinating, but when these seeds are taken out and planted, BOOM! up they come. I believe it is important to get the seeds out of the fridge and into an environment where day to night temps fluctuate as they would in most any climate.
I’m sure opinions on this matter will vary, but my approach has been very successful for me and I have no shortage of seedlings to deal with in any given year.
Paul
*This year I am taking some seed lots and sowing them now to spread out the work and to give some of the more cold hardy hybrid seed a longer period of fluctuating temperatures, just to see how they respond. If it means I gain a few extra weeks of growing season as well, all the better!
Paul,
your answer is detailed, very easy to understand and excellent. Thank you.
" I do wish I could encourage people to plant their seeds in soil once stratification is complete."
Agreed on this too…
in addition to this I believe that seeds should be sown directly into deep beds to allow unhindered root run… the less the roots are played with the better IMO. I use foam fruit & veg boxes that are about 7-8" deep (they are about 50cm long x 40cm wide x about 20cm deep), and I can fit 8-10 of them in my mini-greenhouse. George Thomson uses these foam boxes and has been quoted as saying he can fit something like 3000 seedlings into one of these boxes!!! I don’t sow anywhere near thousands into one of these… most I’ve done in a single box was about 300… and these were all the same (multiflora seeds) that were only going to be used as root stocks so I weeded them out pretty quickly to give the others more room. This idea is based on photos Jim Sproul showed me of his seed beds into which the seeds are sown and left all the growing season… the roots can grow as much as they want and it’s easy to thin out the poor seedlings as they become apparent (I just snip them off at the base with a pair of scissors if they are bigger. The small ones just pull straight out). I’ve also had much better luck this year, in terms of better roots, by mixing in lots of perlite into the mix to create larger air spaces without compromising water holding ability.
George… to put a southern hemisphere spin on what Paul said… in terms of timing etc… I tend to start collecitng hips around March but most are collected around mid-April-early June (just take your cue from the plant). I tend to wait till the first day of winter to put the seeds in the fridge. They are stored in a cool dark place until then. I tend to store them in the hips unless they are big fleshy hips like rugosa hips (last year was cool… I popped the big fleshy rugosa hips in my mouth and ate the sweet pulp and spat the seeds out nice and clean LOL Gotta have some fun!). I find they are easier to remove and come out more cleanly if they are a bit drier. When they are put in the fridge I forget about them for 6 weeks and then start checking… some of the earlier ones, like the multiflora hybrids (hybrid musk type), start really early and I find the smaller the seed the earlier they start. If I notice one starting to germinate I’ll sow the whole lot in that bag into one of the foam boxes. I usually use moist paper towel to stratify my seeds but experimented, with some success, with moist perlite and am currently switchng to moist peat. Once I discover the first germinant I’ll check them every week. If a batch hasn’t started germinating by the end of winter I’ll sow all of them about 2-3 weeks before the beginning of spring. At six weeks into winter here it can still be down to -10 outside so the boxes go into a mini-greenhouse (until I can afford to build a tunnel-house like Paul’s polytubes or a nice big polycarbonate rigid one like Jim’s one (which is where I’m leaning for many reasons)). We can have bad late frosts, and even snow, as late as October so everything stays under plastic until about Nov. and then I like to start hardening them off by opening the doors, and then moving them out under trees and eventually into full sun. Now, some of this year’s seedlings are pushing 3ft tall and have flowered well and are onto their second flush. They are potted into large pots or planted in the ground about now and kept watered over the summer heat. I find that people I speak to in most places on the mainland are about a month ahead of me at the beginning of the season in terms of development and a month behind me at the end of the season ni terms of dropping temperatures.
I better get my germination techniques up to scratch ASAP for this, my first season! My embryo work is only good for extremely precious or impossible-to-germinate rose achenes, it has no place for the germination of hundreds/thousands of achenes.
Simon, it’s always nice to hear from your experiences, thank you. Actually, I especially LOVE your mention of using those deep fruit/veg. polystyrene boxes, what a brilliant idea…they even come with ready-made slits along their bases, ready made drainage holes…LOL…I love practical ideas like this!!! (and of course, thanks is also due to Mr George Thomson for sharing this idea. He is one of our Australian contemporaries, who I have respect for…I would love to chat to him one day).
In addition to replicating your collective advice here on stratification, I am also planning to experiment on a fair percentage of my hip harvest in the following way (to see if I can do away with the whole zip-lock bag/moist medium thing)…
I plan to stratify a percentage of hips in the fridge for the ten weeks suggested, however I am not going to extract the achenes out of them all this time. Then after the ten weeks cold stratification is completed, I am going to open up these hips, and remove and clean the achenes, then immerse them in water for a few days to dissolve out dirt and impurities. Then I’ll put those achenes out to air dry completely, say for several weeks (to kill off fungi). Then I will sow the dried achenes as usual.
I can then compare germination rates this way versus the baggie/moist medium way, and see if there is any dramatic difference in outcomes.
Actually, soaking the achenes for a few days to help dissolve impurities and then drying them in air,
I would like to share my rose production schedule with all of you. I go by holidays.
Start pollinations May 31 (Memorial Day)
All pollinations done by July 4th (Independence day)
Harvest all hips by Halloween
Put hips in frig till Christmas
Clean hips and put seeds in moist paper towels, & back in frig until Valentine Day, then plant seeds.
A few seeds will germinate in between but I just take them out and plant them up.
You know, I just had a thought (thinking aloud here, if that is ok?)…
Since I am in a fairly hot climate here, does it make more sense that I skip cold stratification altogether. Even though this will dramatically reduce the germination rates, it might be a way of selecting for heat tolerant plants “right from the word go”, which is my ultimate goal in breeding roses, here where I live.
Any comments?
I would imagine it would depend what the parents in the crosses were. I doubt there would be enough variation in the genes of cold hardy roses, if these are the ones being used as parents, to make this a viable option. If, on the other hand some of the more heat tolerant species or soecies hybrids are used then maybe this might work… I’ve not tried it. The clinophylla seeds I received recently were sown straight away as were the clinophylla x bracteata seeds… I guess I’ll find out over the next few weeks whether there is anything in this.
Hmmm…
I sowed clinophylla and clinophylla x bracteata straight away, no stratification with good results. I did this instinctively since they are warm climate species.
George, I began years ago not stratifying anything. You will get plenty of germination but it will be more sporadic than when seed is stratified.
After I began hybridizing with hardier types of roses I began to worry more about germination.
After a few years of experimentation I found it more convenient and more productive to stratify all seed. Germination is more predictable. I decided it was easier to process everything at once.
Robert, I am all for anything that makes things easier…there is not enough time to muck around too much, thanks for putting this idea of mine to rest.
George, I think it’s a good idea, but the fact of the matter is I have been hybridizing roses with some purpose of thought now for about 10 years. I’m 50. With luck I may live into my seventies, eighties and beyond, but many don’t. The next couple of decades may be about all the time I have. Hybridizing roses takes time. Any means of enhancing productivity is an asset.
Too right it is! BTW I am 46yo this year, not that far behind, I know exactly what you mean, Robert.
I remember a chat with Ralph about stratifying rose seed. He didn’t put much stock in it. His thought was that Nature produces some seed which will germinate right away, with little to no cold exposure. Others will require varying degrees of cold before they germinate, so there will be something germinating to perpetuate the species no matter what type of winter you experience. His thought was by not stratifying them, your chances of only working with the more heat tolerant, more continual blooming offspring increases. Conversely, stratifying them should prevent the more “tropical” types from germinating until those of greater cold tolerance are ready.
I’ve always kept pollinating until the end. Laurie Chaffin told me years ago she pollinated virtually year round in Yorba Linda and obtained some of her favorite seedlings by collecting green hips and germinating them in spring to early summer. I collected them as they ripened or had the big push to strip the garden when the vermin began paying too much attention to my hips. I held them in baggies with damp toweling in the refrigerator until the week of Thanksgiving (late November) because that’s when the weather cooperates…usually. This year, I didn’t refrigerate anything and it resulted in rapid germination. Far faster than any other year’s germination. I just kept them in the garage until I was ready to plant. Some had germinated in the bags and due to the cooler, damper weather we had when I planted them, most have survived.
Since cold hardiness is something I can’t really test for and don’t need to consider, not stratifying them should theoretically help me by potentially reducing the germination rate (though that doesn’t appear to be the case) and skew my results more toward plants more suited to my climate. It was also a whole lot easier. I’m 55, BTW.