At about the end of June I scarred about 200-300 open pollinated HT achenes in a mixture of 3% hydrogen peroxide in a 1/3 cup of water (soapless mixture A of Don’s guide) for about 12 hours and I sowed them outdoors in seed trays. The temperature did fluctuate between an average of minimums of 3-7C (there were few days that reached 0-3C) and daily highs of 15-21C. About 70 days later I now have 30 seedlings and more are still coming up.
I’m quite happy with the results, the germination rate is currently somewhere between 10-15%. If I get any more hips which are open pollinated I’ll test them in summer conditions.
I’m not sure, but I think this works mainly for HT’s and other china-blooded roses that have less chill requirement. But I could be totally wrong, and look forward to hearing from others who have tried it.
Congrats! My first germinations were accidentally done this way. I sowed them outdoors to stratify over the winter but they wound up sprouting a few weeks later. As already noted, this is fairly common with modern roses descended from tropical and subtropical Chinese roses.
I think it’d be more accurate to describe this as a “no refrigeration” technique rather than “no stratification”. The fluctuations from cool daytime highs and near-freezing lows were sufficient to stratify the seeds into breaking dormancy. This is essentially mimicking the subtropical winter of Southern China in the same way that putting seeds in the refrigerator for four months mimics the temperature winter of Europe.
I assume this is also why rainfall is so helpful in triggering germination. The reversal of cooler temperatures is accompanied by the arrival of thunderstorms that mark the beginning of the rainy season in Southern and Southeast Asia.
This was my first time trying this technique. I used it on hybrid tea seeds, so I can’t say if it’ll work on other types of roses. I got the seeds from a friend that was planning on chucking them, so I thought I might as well experiment.
I slice the hips open with a knife before sowing them by hand. I have seen the blender method you mentioned in other threads, I’ll have to try it when I have some more hips
