Tall balloon columns need a base to keep them from falling over. Follow these instructions on how to make a balloon column base for a sturdy base you can use over and over again.
Screw a 1/2″ floor flange pipe fitting attached to a 1/2″ thick, 12 inch square blog of wood.
Find PVC pipe or a wooden dowel in a diameter that will fit into the opening of your floor fitting and is the height of your intended column. Secure the pipe or dowel to the fitting by reinforcing it with electrical tape or duct tape. Wrap the balloons around the pipe or dowel to shape your column. The board at the base of your column should keep it sturdy and prevent toppling.
You can find the floor fitting and PVC pipe in the pipe and fittings section of most home improvement centers. The dowels can also be found at home improvement centers and sometimes at your local craft store.