With winter setting in and my gardening blues right along with it, I am spending some time creating my lists of planned crosses for the 2024 season. One thing I am looking into is Rosa setigera this year. I was curious if any of you have feedback or information on remontancy with its hybrids. I gather that it would take successive generations of hybridizing to get remontancy and will vary on the pollen/seed parent used - but if you have any suggestions or ideas how many generations down from an initial cross with the species you see or would expect to see remontancy. I see that setigera reliably produces hips, but whether or not is it best suited as pollen or seed parent is another question. In addition to the straight species, I recently obtained a Long John Silver from Rogue Valley and see that it is both hardy and has large flowers, but appears to bloom only once as well.
Welcome Justin! R. setigera has some unusual habits compared to all other roses, mainly that plants are normally either male or female and can’t be used for breeding in both directions. There’s been quite a bit of discussion of this issue here on the forum. I’ll include some links to those discussions that I can find. Hope the info helps.
You can recover fully remontant offspring from the species in the F2 generation if you cross it and then the resulting F1 seedlings with fully remontant roses. I’m not sure if Long John Silver has any fertility, but if it does, you could expect around half of the seedlings from such a hybrid to be remontant if has been crossed with a fully remontant rose. Starting out with a functionally female R. setigera individual/clone is probably the easiest and most flexible approach if you’re starting with the species.
I don’t believe much of what I’ve read about the R setigera hybrids. Horvath was about the only person to systematically pursue hybrids. He was responsible for some of the very early ones in New Jersey that are often attributed to another breeder. Doubloons was his biggest, best, bright gold success, raised near Lake Erie in Ohio. It is hardy in Wichita KS, but scarcely a00 mils north, although the new hardiness zones indicate it might make it to a few degrees below zero especially with some protection… But we have no notion of how many generations from R. set it actually is. Somewhere years ago I wrote an article that appeared in the newsletter about all this.
I have been trying hard to get offspring of the pollen on many common types. So far only Jeannie LaJoie has set seed but no germinations from those so far in 2 yr serious pollinating. I get lots of seedlings on R set with many pollens apparently, but all the seedlings look like selfs. You have to be up before dawn, or emasculate the night before and cover to avoid selfing. I really don’t know how Horvath managed to get results, but he was noted as a successful breeder. Maybe mainly diploids with some triploids sprnkled in.
If anyone wants seedlings of R. set I’d be happy to ship some in spring. They are very tiny at germination but grow up to a decent size in a couple months. I have the seedlings mainly from a very fertile female rose out of the old rose gardens at K-State, and also from one growing the MN arboretum (courtesy of D. Zlesak). I have them still on my front porch but they have to go into a cold room for the rest of the winter very soon so they don’t dehydrate in their original six-pak state. My e-mail is ldavis and I’m at the university mentioned above.
I’ve made quite a few successful crosses on R. setigera, which actually cannot self-pollinate because it is functionally dioecious. I have no functionally male clones here, so getting any pure R. setigera seedlings is impossible. The inability of its pollen to function with non-setigera roses has been noted previously by David Zlesak, so it clearly works best/only as a seed parent (obviously, you will need to have a functionally female specimen). I’ve personally raised repeat-blooming seedlings from crosses on ‘Baltimore Belle’, which itself is a first-generation seedling of R. setigera.
That is great to know ‘Baltimore Belle’ can set seed and you obtained rebloomers Stefan. I wanted to try some of the early climbing hybrids, but wonder how easily I can overwinter them to bloom in zone 4. I also have been slow to try too because of limited fertility it seems. Ellen was a grad student at Texas A&M and went to the Chambersville Tree Farm to pollinate their various ramblers/climbers in the collection that were R. setigera hybrids and I think didn’t get much seed set. I chromosome doubled a female R. setigera seedling and it has been a link to eventually getting some repeat bloomers with modern tetraploid shrubs.
Here is a repeat bloomer I love a lot out of it (this 4x clone x a shrub seedling and then that hybrid crossed to another repeat blooming shrub seedling). It wish it was fertile. It is for sure not female fertile and I should look at its pollen.
Here’s a paper colleagues and I wrote studying the reproductive biology of R. setigera. It works well as a female at the diploid level with diploid polyantha-like males. I suspect since polys are based on related rose species (R. multiflora and R. wichurana) that they cross pretty well and hybrids are relatively fertile.
Here’s a fun (flowered) but otherwise kind of wretched little everblooming shrub from a 2016 cross between ‘Baltimore Belle’ and Yellow Brick Road. Its growth is awkward and it is viciously thorny (both clearly courtesy of YBR); the leaves are pretty but blackspot resistance is not great, and its canes are more susceptible to disease than those of either parent. It might have finally died now because of the disease issues. For what it’s worth, ‘Baltimore Belle’ looks fantastic through flowering but does get some blackspot after flowering, after which it recovers with clean, graceful growth through the end of the season (probably in part because its other parent was a Noisette, because R. setigera stops earlier and becomes more diseased as the summer progresses). ‘Baltimore Belle’ produces occasional open-pollinated hips most years.
The buds and freshly opened flowers are more intensely colored; the fully opened blooms soften to warm pink and cream. It’s pleasantly scented, at least, with fragrance that reminds me a little of cherry Jolly Ranchers.
You could also consider ‘American Pillar’. It has both R. wichuraiana and R. setigera in its parentage (2nd generation). It probably has remontancy capabilities. Probably 50% if you cross it with a good repeating rose. 'Chaplin's Pink Cluster' Rose Chaplin got this one from it. Looking at its offspring, you can use it both as seed and pollen parent.
I want to say thank you to everyone who contributed information to this topic! I have learned a great deal about the use of setigera through each reply. It seems we have a lot of research to do in discovering the extent of the supposed Horvath cultivars and in the use of several hybrids for remontancy. I will keep you all posted with any updates and my specimens/hybrids into the next growing season!