I wonder if there would be a benefit to collecting all of the penzance briars. Maybe by crossing them, remontantcy and modern featutes might find their way out of the primordial ooze that is trapped in these plants. The HPs might come out a bit when recombined, and the foetida genes might come together to create a fragrant foliage yellow that has a mostly species like charm. Then cross those with the HP briars and very primitive kind of reflowering sweetbriar might emerge. The benefit is that the plants would be impossible to kill, and would be a great starting point for a knock out or carefree kind of shrub rose.

I'm sure that there would be faster ways to get there though. Applejack backcrossed to its parent, Goldbusch, and maybe just crossing a hardy continuous flowering rose with the species [rubiginosa] itself. It doesn't seem to pass the fragrant foliage in the first generation though. It seems to be a highly dormant set of genes that need to be reinforced several times to express themselves.