Sweet Smelling Surprise

I was mowing in the lower garden on Labor Day (a fitting activity for the day, but hardly a "holiday" from work for me), and as I rounded a corner I received a momentary sensation of being immersed in honey.  I didn't stop immediately, but on the second round, when I was struck again at the same corner with a sweet scent, I hit the brakes and looked around.   There, draping over ‘Double Red’ Rose of Sharon (Hibiscus syriacus), were these little white flowers that were not supposed to be there.  

These are, of course, a Sweet Autumn Clematis (Clematis paniculata or C. ternifolia, whatever it is now), which self-seeded itself somewhere next to this trellis and grew unnoticed until now.  This trellis is flanked on either end by two Wisteria vines, which provide both color and a great fragrance each Spring, but in September they're a bit less noticeable, merely serving as a green window to view farther parts of my garden.  The growth of the Wisteria on that end is so thick that I couldn't easily find the Clematis vine source.

The dilemma now, of course, is whether to leave the Clematis there or to move or destroy it.  C. paniculata seems to grow very well here in this climate, and if I leave it here, it may eventually strangle the Wisteria ('Amethyst Falls’) on that end, and the adjacent Rose of Sharon.  I have two other C. paniculata, so one could argue that I've got plenty of it in my garden, but on the other hand, I'm not sure you can ever have too much of that vanilla-scented vine in an otherwise dreary August garden.  'Amethyst Falls' is not nearly as scented in the Spring as the Wisteria sinensis on the other end of the trellis, but it does rebloom for me and it is more dependable in late freezes than the W. sinensis.   

Decisions, decisions.  Are there ever any end to them in the garden? Can I hope that the Wisteria will keep the Clematis in check, allowing each year only these few delightful sprigs of scent to pull me into the shade on a hot day?