Fascinating! I wonder if it is an insufficient winter chill thing? I know the seeds need extended 40 degree stratification...
I can't say that I've ever tried to 'domesticate'
them, but I sure have had trouble with them volunteering wherever they wish in my gardens both in the midwest and here in the west as well as being very difficult to discourage once they get those taproots going.
I planted A. tuberosa on purpose and it seeds itself around quite freely. I have let some of them go in places really unsuited for their eventual size and later dug them out and relocated them somewhere more accommodating...transplants took and the originals came back too. I surrendered to the A. tuberosa shrubs where they don't fit but I cut them to the ground after their fall blooms and throw the whole thing--aphids and summer seed pods in the trash. I have another A. speciosa clump in a really unsuitable location that I have dug out four years in a row and it keeps coming back too, although this last year it seemed a little daunted for a change so I think It might give up one of these next few years. I know it probably sounds horrendous for those of you who have trouble growing milkweeds that I would be trying to kill one...there are hundreds more not far away, if that helps any...
And there is a lovely patch of A. asperula just up the hill from me...I collected some seed and I'm *thinking* about planting it..but feeling a little reluctant, too.
Anyway, your vine is an impressive specimen and I'm glad that it likes domestication for you!
