Hello, new here and first post. I live in central NY, and our roses haven’t even started blooming yet, but I have nice buds coming along. I’ve been reading through many of the forums, and I have a friend who has been experimentally crossing his roses. I found this website in search of more info. The majority of my roses are DA’s, or cold hardy Canadian roses for my zone 5a/grow as a zone 4 for most roses. My friend was telling me to “try not to mix the ploidy (?) of roses”, but for the life of me, can’t find much info online about that, probably due to using improper search terms. Since they are modern roses, do DAs generally work well together? I have a Heritage next to an Abraham Darby for one example, and then a bunch of others… this will be my first time, so am just dipping my toes in! I also have a nice John Cabot, that throws beautiful hips in the fall- worth trying?
I really wouldn’t worry too much about ploidy just starting out unless the science behind it truly interests you. Roses are weird in that interploidy hybridization doesn’t necessarily result in sterility. It’s really less of a concern unless you’re working with species or old diploid roses, and even then those crosses still frequently defy traditional logic and hybridize to make fertile offspring. Most David Austin roses are tetraploid or triploid, and provided they are fertile they should cross with each other fine. I don’t grow David Austin roses but have seen that Abraham Darby makes for a good seed parent.
It’s all worth trying, if only for the trial and error. You’ll never know what sets hips or creates healthy seedlings in your climate until you start. The hands on experience of making crosses and germinating seeds, even just open-pollinated hips, will prove more valuable than anything else in your first year.