PhotoComments & Questions 
Rosa canina L.  rose photo courtesy of member Jeffrey
Discussion id : 105-787
most recent 3 OCT 17 HIDE POSTS
 
Initial post 1 OCT 17 by Margaret Furness
The reference from 1938 is worth noting.
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Reply #1 of 17 posted 1 OCT 17 by Andrew from Dolton
Rubiginosa is the same, nothing for two years then up they come like mustard and cress.
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Reply #3 of 17 posted 1 OCT 17 by Jeffrey
Hi, Andrew! I'm wondering if the seeds need multiple stratification: warm-cold-warm-cold? I've germinated most of my seeds with just the cold stratification. Usually I get a bazillion seedlings. I'll post my progress as I go along.
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Reply #2 of 17 posted 1 OCT 17 by Jeffrey
I'll check the reference you mentioned, Margaret! Thanks so much! It's interesting to note how many of these (I assume) R. canina plants pop up in the hedge rows around here. I know that in general, the rows have been purposely planted, so I'm likely finding selections of R. canina. That said, there's quite a bit of variation in the quantity of hips per plant, and the manner in which the hips are presented, ie: clusters of hips vs. single hips. I've been harvesting from plants bearing the most hips, especially those in clusters, hoping for the most floriferous seedlings..
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Reply #4 of 17 posted 1 OCT 17 by Andrew from Dolton
Hello Jeffrey,
I sowed the seeds in autumn of 2015, kept them on the kitchen window sill but nothing grew. They were kept cool and shaded through the following summer then taken inside in February of this year. They started germinating after just a week.
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Reply #6 of 17 posted 1 OCT 17 by Jeffrey
I put my seeds in damp vermiculite, store them in the refrigerator for 30 to 90 days, sometimes the seeds sprout while in the bag, so I have to watch closely. If I see root tips developing, I sow the seedlings in community trays. I almost always get great germination in a week or two. The temperature has to be below 40ºF and above 32ºF. The narrow range deactivates the chemical that inhibits germination. Freezing can kill the embryo, and warmer temps, temps we'd be comfortable, aren't cold enough. It's an interesting mechanism, I think.
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Reply #7 of 17 posted 1 OCT 17 by Andrew from Dolton
Just be aware that in some parts of your country these introduced species are invasive weeds.
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Reply #8 of 17 posted 1 OCT 17 by Jeffrey
I just triple checked the r. canina situation in California. It is in fact loose out west, but the USDA listing has it as "present" in certain counties. I'll look at this more closely. We have so many invasives: scotch broom, acacia, blackberry, etc... I definitely don't want to worsen the situation. Thanks for the reminder.
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Reply #9 of 17 posted 1 OCT 17 by Andrew from Dolton
You can always do what Patricia Routley does and remove the hips before they become soft and birds (in her case parrots) eat them and distribute the seeds.
In your climate it will probably require plenty of water and protection from the mid-day sun.
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Reply #10 of 17 posted 1 OCT 17 by Jeffrey
I have parrots, too. So far they only get into my neighbor's cotoneaster. I will be growing these in Petaluma, farther north, but to strip a big bush, or in fact several big bushes might be too much to deal with. I will be contain the hips when I make crosses, if I do this, but still, the problem could get out of hand. I'll check with my county agent when I get back. If it's an invasive then I'll rethink this.

I so appreciate your input. I wish I had time to visit your garden, if you permit such a thing. Alas, I'm an impoverished senior student at university.
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Reply #11 of 17 posted 1 OCT 17 by Jeffrey
I checked the USDA list of introduced, invasive, and noxious plants for California more thoroughly, and R. canina is not on it. Neither is R. glauca, the other hips I found. R. canina does show as being in the state, however. To be safe, I'll send a note to the Agent to be sure.
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Reply #12 of 17 posted 1 OCT 17 by Andrew from Dolton
If they are not on any invasive list would you like me to send you seeds of Rosa arvensis and Rosa dumalis?
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Reply #13 of 17 posted 2 OCT 17 by Jeffrey
Wow! That'd be swell. R. arvensis for sure. I have some R. dumalis chilling in my fridge in San Francisco right now, but if yours are open pollinated, and there's a chance of an interesting bee-assisted cross, send 'em on! I think to San Francisco, not here. I'm not sure I can even take the ones I have through customs. To declare or not to declare, that is the question.

I'll send a personal note with my address.
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Reply #14 of 17 posted 2 OCT 17 by Margaret Furness
I'm being a party-spoiler again... The fines for both sender and recipient of quarantine-banned items are massive, even if one party is innocent. And it's not worth it, given how much a country suffers from pest species.
For interest, and off at a tangent, have a look at
abc.net.au/news/science/2017-09-29/japan-tsunami-rubbish-rafting-invasive-species/8987708
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Reply #15 of 17 posted 2 OCT 17 by Andrew from Dolton
I never realised it was illegal to send seeds. We have our own introduced problems in the old world too. I am just seeing the first effects on ash saplings in front of my cottage of Chalara, or ash die back disease, is as potentially damaging as Dutch elm disease was fifty years ago.
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Reply #16 of 17 posted 2 OCT 17 by Margaret Furness
Sending seeds isn't something I've gone into in detail. Some are OK, those that have a risk of becoming invasive are frowned upon. Always ask first, is the answer.
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Reply #17 of 17 posted 3 OCT 17 by Jeffrey
I love this lively exchange, I really do, but I had no idea it was so complicated. I can check on R. arvensis seeds as to invasiveness, and if I need a permit to bring them back with me. I assume the Floribunda seeds I have are OK, but I won't take a chance. The company that bred that rose is here near Chester. Their company ships overseas, so I may order a plant or two for my own hips.

So... Andrew... Have you done any crosses with R. arvensis?
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Reply #5 of 17 posted 1 OCT 17 by Jeffrey
Margaret, I just looked at the reference you so kindly mentioned. Thank-you again. The two-year period before germination, and Andrew's note makes me think these seeds require two cycles of warm/cold stratification. I've had success by going 30 days moist warm, thirty days moist cold, then repeat. It shortens the period for germination by a lot.
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