As the former owner a c. 1940s true Williamsburg-Colonial-revival house for
     20 plus years (it's going to support me in my old age), I can testify first
     hand to the many hateful features of ivy.  Ralph is absutely right--the
     nasty little finger things DO NOT COME OFF.  At one point I poisoned all
     the ivy, thinking it would eventually fall off.  Hah--10 years later it was
     still there all brown and ugly.  Yuch.

     On the other hand, I had something I think was called Boston Ivy that was
     beautiful.  It was much less heavy a cover than the American stuff, turned
     a nice mahogany color in the fall, and lost its leaves in the winter.  The
     best part was that it was so loosely attached to the wall that you could
     stand on the ground, pull on one of the stems and pull the whole huge
     length of that particular part of the vine off--all the way up to the roof.
      Not only did that improve the look of the wall, but it was wonderful fun
     to do.  A great sense of power.

     I would recommend that stuff to anyone, though I don't know whether it
     grows north of Washington, DC.

     Marilyn Harper