Ah yes the lure of Bindweed (I'm assuming that's what you meant, I know of no weed that exclusively colonizes hobo's stick bundles

). On top of the invasiveness of Field Bindweed (i.e. Morning Glory) I have a nagging suspicion, based on the many wild patches I have observed, that when morning glory is allowed to go wild on it's own, the flowers have a tendency to revert back to their wild colors. Occasionally you'll see a pink or purple striped one or even one that still has it's domestic color* but normally in a few generations it's gone back to dead white.
As maddening as Morning Glory can be, I know of worse. When I say I save the stuff I find in my sorting for planting I mean nearly everything, ICLUDING the bindweed seeds (since I don't know the species of most of what I find, from this point on I will be using the term "bindweeds" to cover all members of the
Convulvulacae I have found) And bindweed seed is as near to a universal contaminant of bulk seed as I have ever seen; some form or other shows up in
everything .
Five or six years ago, I sorted out all of the bindweed seeds I had accumulated this way (by that point they filled a pint bottle to the top)by appearance and did do a plant-out, with more or less the same goal as you; to find a fast growing vine with attractive flowers. By and large the experiment was a near fiasco. Almost none of them flowered at all, due to being species coming from tropical places and, hence being used to longer days than I had. And most ended up growing all over everything that year (the saving grace is that 1. Being tropical they tended to lack the cold hardy roots of more temperate bindweeds and 2. I had been smart enough to do all of them in pots so the problem was a one season affair.
The worst of the worst was/is something I nicknamed "grasp vine" since I have no clue what species it actually is even after a LOT of looking up (I have vague memories of seeing something like it online years ago referred to as "Cotton Leaved Morning Glory [NOT Ivy Leaved, I've had that too and it is different] but I have never found that reference again)
Everything that is bad about morning glory this has and then some. It's huge, and grows very rapidly (it can actually strangle other bindweeds to death) It's vines are COVERED with coarse dark hair. It's leaves as both my name and the possible real one suggest are very different from normal bindweed's. Instead of the standard cardioid (heart shape) or saggitate (arrowhead shape) leaf its' leaves are more or less palmate (hand shaped) each is divided into five to seven to nine more or less equal finger like lobes (the bigger the leaf the more lobes )
Unlike a lot of the bindweeds in the experiment, Grasp vine actually CAN go through it's full reproductive cycle here, though I have never gotten mature seed (the first year, the vines were destroyed by a storm, the second by the house painters who no one told me were doing the Iron railings of the house as well. However unlike normal bindweeds, Grasp vine produces NO flowers. Instead it produces what I can only describe as "seed balls" These sort of resemble convention bindweed flower buds (at least the single ones do, the plant makes aggregate ones as well) However these buds never actually open. Eventually bindweed like seed pods just develop in there, presumably by self pollination.
Never having seen mature seed out of the pod I can't be sure, but I think the seeds is typical bindweed wedge shaped and grey or black (next message)