My vines certainly don't shy away from growing on other nearby vines. I often find myself unwinding vines that have grown together to spread them out only to come back a week later to find that they have wrapped themselves around each other again. Sometimes, if a vine hasn't lived up to expectations, I plant another type of vine to grow up the disappointing one, leaving the original one in place just to support the new vine.

I wonder if the woodiness and/or weight of the vines makes a difference? Morning glories will certainly climb on anything! The article in the link talked about tendrils as the things doing the 'tasting' and not all vines have tendrils. So I wonder if their findings only apply to vines with particular characteristics...? I will now certainly be paying more attention to how vines growing with other vines support each other - or not....

That is very interesting woody. I know that my Actinidia arguta 'Issai' has entwined with the climbing Hydrangea (as well as Miscanthus s. 'Strictus'). The Hydrangea is a strong growers so it makes sense that the Actinidia would utilize it, clearly no repulsion to it.

I will be paying more attention as well. I don't ever recall any Clematis trying to cling to either of the afore mentioned vines. I have certainly had them try to use other perennials though such as Iris sibirica.