What about us here in Oz
That looks like pretty good hip set. Are all these hybrids fertile.
Adam , all these R. Virginiana F1 offspring produce abundant hips full of seed.
I felt that when I did the Sympathie X R. virginiana the septet formula was 3+ 1. Looking at the crosses I did with these R. Virg (F1), the reaction to tetraploid pollen on them gave quite unusual results and not like those of a balanced tetraploid. When I used the pollen from these F1 R. Virg hybrids on known tetraploids the reaction was like they had been fertilized by a diploid. Breeding with these F1 Hybrids , I will always keep in mind of this possible 3+1 setup, could also be very handy.