It LOVES California. I say that because I see very old ones all over - not tended, but still blooming like mad. I haven't seen noticeable disease on any, either. There is one up the street from our house. We just saw it walking back from dinner. It has a Dr. Huey rootstock flower on the bottom of it. I have told the lady who lives in that house how to take off the rootstock several times in the last 5 years. Nothing. My point is, JC must be pretty strong because it is still 95% of that plant. Jackie

I'm not familiar with this particular climber but the good news is that is IS young so less is morel! The most important thing I see is that you need to get some of those canes growing more toward a horizontal. See that cane on the far left? I'd pull it as close to horizontal as you can. The idea is once you have it designated as a main cane anything growing off of it is a lateral and should be pruned. It looks like that same cane has a lateral that's coming off to the right a foot or so off the ground. You have a choice: you can decide it's a lateral and prune it off at 6-12 inches OR you can decide to treat it like another main cane and pull it horizontal too. (On a young bush I'd probably make it a main cane.)Then prune off anything growing off of it. Really, at this stage you are trying to organize more than you are trying to prune. In general I'd try to get this rose to grow more in a fan shape so that the canes that you keep are at a 45° to 90° degrees. You don't get lateral breaks from an upright cane and blooms come off laterals--more laterals more blooms. After pulling the left one to the left, see if you can't pull the canes on the right to fan out to the right. It's alright if a "main cane" doesn't originate from all the way down at the base, but it would be helpful if it was coming from the bottom third of the plant. Someone posted a link to a way to attach canes to walls that looks pretty cool. I've never used it but it might be something that works for you in trying to get those canes horizontal. https://sugru.com/home-diy/no-drill-diy-garden-trellisHope that helps...

Well the soil looks overly water retentive, but your problem is probably that there are no new growth buds left after you stripped the growth off. If none have broken in a couple of years, I'd say...sorry, it's dead (well not, but never going to grow).

When you say you thought "it was a goner", do you mean the plant appeared dead, or what? Are the white flowers similar to what Joseph's Coat should look like, only in white? Or, are they smaller and single? If the plant appeared dead and now there is something growing and flowering there, perhaps it may have been budded on R. multiflora and the stock is now suckering. Or, if you have multiflora growing in the area, perhaps birds (or other critters) dropped seeds which have germinated near where the Joseph's Coat grew and are now flowering. R. multiflora looks like this. If you mean the Joseph's Coat just looked terrible but wasn't dead and it's now flowering as expected, only instead of the proper coloring, the flowers are washed out toward white, you may have had some freeze damage or the weather has influenced the flower pigmentation, which will probably be more normal once the heat arrives and the plant starts growing and flowering normally. Photos of what you're seeing would probably help diagnose the issue.