Kevin,
Good to know that the vivid dark pink a likely marmoreum trait. 'Saharasonne' is about as hairless as it gets and rarely blooms, so I'd say that pretty much rules out arachnoideum as a genetic contributor.
I have rebought 'Rubicon' again this year because I love the shape of it. The color is interesting to, but it hates our winters here. My most recent soil mix is pretty nice, it uses potting soil instead of native soil as a base, something I'd hoped to avoid but seems to yeild better results, Ive got rubicon potted up in that and I'm hoping it makes it to spring this time around. I have half a mind to bring it in with the tenders, but if it takes that much pampering perhaps I shouldn't be looking to use it as a parent. I've never seen the improved version available for sale.
-Sol
