The two also differ in plant size and hardiness, if GST is to be believed:

"In my experience [Rosa roxburghii var. roxburghii] is not so vigorous nor so hardy as the single type, and is much smaller in growth."

That would stand to reason, considering R. roxburghii var. roxburghii is a cultivated form, whereas R. roxburghii var. normalis is the wild form.

Thank you Ross! Good to know.

I must ask, perhaps you may know? But is there a difference between the rose hips? I figured that the R.Roxburghii has many petals unlike it's nature form R.Roxburghii normalis that it may have trouble setting hips

I can't comment on whether there's a difference in hip production -- I've seen only "normalis" in person. But I will say that not all double roses have trouble setting hips: the very full-petaled 'James Galway' is one of my better hip-producers!

Thanks again Ross! You're completely right.

The double Chestnut rose was found in China several decades before the single one. They are both listed as species roses in HMF.

I saw the double in Mike Lowe's NH garden and the bush was very attractive.

In Lakeland Florida, they both produced hips for us, although a lot more of them on normalis. Also, the double form repeated reasonably well throughout the year, whereas the single form was strictly once-blooming.

@malcolm_manners This right here is gold information, this is the stuff that I was looking for. So, THANK you.

So gathered from your information I need to decide on which Roxburghii form to get. . .

It may be odd Malcolm, but which is your favorite and why?

Thank you.

@Ian Stewart: Zone 6 Western Kentucky, USA Malcom Manners is in florida in a warmer zone and probably a longer growing time than a zone 6. While Malcom Manners is a great rosarian, please keep in mind that his experience is not the rule of thumb. Having grown both the single and the double forms of the chestnut rose in zone 6, I would say not to expect a reliable repeat from the double. I did get hips from the single form, but I have not had the luck of getting hips from the double.

While taking nothing from the advice of any of the rose growers, it is important to remember that not all roses behave the same in all zones. Not all zone 6 experiences are going to be the same either. A desert zone 6 is going to be different than a humid zone 6 or a wet zone 6 or a snowy zone 6, etc.

Take people's advice, but if you are wanting recommendations for your yard, in your area, contact other local rose growers (rose society is probably the best place) or go to a public rose garden, or a botanical garden and see what grows best for your area and go from there.

Generally expect roses that are listed to be either once bloomers with occasional repeat blooming be, for the most part only once bloomers in colder climates than warmer.

Again, not taking anything from Malcom, or anyone else, but your location matters for your experience.

Very wise advice @Brandon Garner, and extremely grateful that you have pointed such out.

"Just because it grows good in another climate doesn't mean it will do good in yours"

Facts. Straight facts.

Now . . . You say that neither repeat bloom well? Interesting...Will take this into thought. Also, I believe you right about the double rarely setting hips. It's quite reasonable even. And not to say @Dr.Manners here is wrong, because I believe he is located in Florida so it is much hotter down there so the blooms may blow quicker thus making it easier for fertilization for hips.

Thank you @Brandon

Now, Dr.Manners, if you are still reading about this thread, I have a question for you.

For the past week I've been researching the "Repeat blooming Swamp rose".

I was about to buy it, but wanted more information about it. When I saw that "Dr.Manners" discovered it from a Rose Hybridization Association thread, I nearly couldn't believe it. "There's no way that this Manners guy commented on one of my Houzz post and he had discovered the rose I've been looking to buy." I thought. I honestly have never heard of your name before.

So I checked HMF and surely enough you were on there.

It is a great pleasure to get to speak with you, but it would be a even worse regret not to ask you about the Repeat blooming Swamp rose..Like..you discovered the thing!

Lol..to the point, have you had any luck with the seeds to it? Do they also have remontant genes?

Apologies for such a long paragraph, @Brandon, @Manners

Agreed with all the comments about climate and location being imporant, and I would certainly agree that Florida experience won't always match cold or dry climate experience.

As for the swamp rose -- that's an interesting situation. HMF is confusing, in that there are different roses involved. R. palustris scandens is a climbing form that sometimes repeats and (AFAIK) is always somewhat double. Then the wild-type R. palustris, which should be a shrub and normally does not repeat, and should also have single (5-petal) flowers. The form that I found in the Green Swamp. Sumter County Florida, decades ago, is in every way identical to the "standard" wild type, except that, in central Florida, it flowers almost constantly. Not just a flower here and there; really good bloom. I know some of the Florida nurseries have that form, but I'm not sure who else does. And I'm not sure how it would behave in a different climate.

@Dr.Manners I believe this could possibly be it! It's from Rose Petals nurseries, located in Florda.

If so, I definitely am going to buy it.

I find it very interesting, as a species rose to rebloom. So I might as well get it and experiment with it.