Simon, or others, e-mail me and I can send seeds, even to Australia. The mother plant came from along Wabaunsee Rd, abt 1 mi N Interstate 70 mi 324 (measured W to E)in KS, 30 mi W of Topeka. It was blooming early Oct (our fall) in the verge that had been regularly mowed all summer. I’ve had it maybe 20 yr in my backyard. (I think maybe I sent a note to the RHA newsletter at that time.) If the first hips are removed, it reblooms, but I’ve never pushed it as late as mid-Aug, never mind Oct. Flower is good sized, attractive mid-pink. Clusters of 25 or more on canes newly arising from base in spring, fewer on old wood. No disease, few insect pests. Yellow fall foliage. I tried various pollens onto it and didn’t get what looked like hybrids. But the seeds germinated well enough (25%) with conventional treatment of stratifying in moist peat.
Thank you for the offer.
An email sent.
Sorry Larry… only just saw this post… how does it go in very hot humid environments (USDA zones 9b and upwards… Even here in Tasmania I am stilled rated at USDA zone 9b - see image)?
Simon,
Your climate rates as maritime temperate and the USDA hardiness map is solely for winter low temps. I expect there is enough chill for blooming, but perhaps not. That would be the limiting factor, not summer’s heat. We regularly have highs that exceed anything ever reported in Tasmania. Humidity varies widely acrosss the natural range which goes eastward from here into parts with typically 80-100 % rel hum many summer days- IA, IL,IN,MO. But this one certainly is better adapted to drought and cold.
Be aware that Joly and Bruneau have showm with molecular markers that you really can’t distinguish R arkansana from R carolina and R virginiana. It is their ranges that differ. There are some morphological variations, sometimes. Also the diploids like R blanda, are very similar to the tetraploids like R arkansana at a molecular level. But also bear in mind that the chimpanzee and Glenn Beck differ by less than 1 % from modern humans.
I’m betting there are adaptational differences, biotypes, as we commonly see with species that have a wide range. Winter hardiness is typically less, or even absent in southern types compared to northern types. This gets the mass propagation folks into trouble regularly. So this accession of R arkansana will be of benefit to you perhaps for some disease resistance traits but perhaps not much else. It doesn’t get our local blackspot races, nor mildew. It has a fungus, perhaps a rust, now in autumn, but not one that will defoliate it. I’ll try to post a photo when I can.
Thanks Larry,
I’m not so much worried about temperature highs here in Tasmania, that is why I moved here… I hate the extreme heat. I am thinking more about the heat and humidity on mainland Australia that is very much higher than anything we get down here. How would the seed store? I’m in early spring here… so I won’t be putting anything in the fridge until about June next year. Does storage like this affect its chances of germination?
Guys, see the link below, showing R. Arkansana hips grown in South Australia.
Simon, if you want this seed badly enough, I am only too happy to extract the embryos and germinate them, just for you!
That’s ok George… I’ve been doing them myself for about a year now after Don sent me his manuscript for ‘testing’ some time ago… I just don’t like doing it in preference to normal germination and I’m a patient person 
ok Simon.
hmmmm… probably not a year… can’t remember… maybe 8 months. Was at the end of last season anyway… suffering from CRAFT syndrome…