At what point in time is further pollenation impractical? end of summer? early Autumn?
Simply put, it depends on your climate. Heps take around 3 to four months to ripen (depeding on weather and cultivar I imagine – i don’t pay that close attention as I am in the south) so work backwards from when you expect killing frosts.
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Welcome, jumpingjack! Precisely. When I lived in a hot area, I had to have my pollinations completed in time for all seeds to be mature for planting in November when the temperatures were appropriate and if we were to receive rains, they would begin. Now I live in a more coastal climate and I can literally plant rose seeds and obtain successful germination nearly year round. The temperatures remain mild enough, without extreme heat spikes, to safely plant and allow seeds to germinate. It all depends upon when your conditions are appropriate to safely plant and germinate the seeds.
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Thank you roseseek. I live in Central west NSW., Australia. Summers are hot winters cool but very few frosts. I have been a commercial rose grower for many years, now retired . breeding is new to me and the conditions for successful seed germination are still a bit mysterious. I am very interested in your experiences in the different climates. For instance do you still stratify your seeds?
Congratulations on your retirement! When I lived where summer was hot and dry, I would store my seeds in the refrigerator until the end of November (when the weather used to cool and rains used to begin) under the impression that would help prevent them from germinating prior to when I wanted them to. Then, I ran into the issue of my significant other really not appreciating all those baggies of damp “dirt” in the refrigerator so, I began just leaving them out in an unused room until planting. They didn’t germinate until they received the cool “winter” temps and several rains and were actually under soil, so refrigeration wasn’t necessary to prevent germination and, after having NOT refrigerated them for a number of years now, it honestly appears if you’re working with modern roses and many species, artificial “cold stratification” is not really required for good germination. My home remains in the high 60s F during much of the year so that’s the usual temperature the seeds are held under. Often they are dry in glass baby food jars, open to the air. I don’t like sealing them in plastic bags as any moisture results in mold. Once they’re planted and start getting watered, they germinate.
In the old hotter climate, I had to plant toward the end of November to prevent them from frying in the heat, either prior to actually germinating or once they started. Here, because IF we receive anything in the really “hot” range, it’s going to appear in September or October, I can plant as late as May or June and any time after the “heat” happens. We most often get about a week or so of real “heat”. The best part of living in close proximity to the Pacific Ocean is it’s a marvelous refrigeration device. It gets chilly and damp and we get enough “winter chill” for many stone fruits as well as flowering plants which demand it, and we’re able to grow tropicals which can withstand temps to the low forties. So, in my experience, refrigerating your seeds isn’t necessary as long as you’re going to get some chill time outdoors.
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I’m in Sydney…so similar temps just less of the extremes when they occur. I tend to sow early march outdoors (and then as anything ripens). As long as temps dip down to 15c and below (even if just at night) germination seems to occur, if temps haven’t gotten below that for a bit germination seems to stop.
I don’t stratify, I tried I got mold, I don’t want mold in the fridge near food. Things that get harvested before I sow because their hips will be mushy/over ripe by the time of sowing (ie rugosa) just end up in paper envelopes in a cupboard. I’m lowest possible effort with it and I’m not having any real issues, even from the cold hardy species that you’d think would want far more chill, still germinate.
Just play around, try as low effort and as high effort as you’d be willing to be and anything in between and see what works for you. It doesn’t seem to need to be as complicated as some make it in our general sort of climate. Biggest hurdle is direct sun in summer…so much self culling.
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