If yours is a vine form - If you were to prune it, I would think proper
pollarding may be something to consider.

http://www.treedictionary.com/DICT20...ing/index.html

Sincerely,
John A. Keslick, Jr.
Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.