Planted Tank Guru
Join Date: Mar 2009
Location: Madison, Wisconsin
Just chop it off on top, but leave a few leaf nodes on the bottom so it can resprout. I like to use a sharp razor blade for pruning because it doesn't crush the stem like a scissors.
The cuttings might root for you if you suspend the cut end it in water. You might also be able to plant it underwater. Lizard's tail will also grow underwater.