I have been looking for an excuse to try a ribbon topiary tree. These are done in the colors of their future colleges. The base is stuffed with a laundry bag and rolls of quarters for laundry.

For the topiary, I used 5 spools of 7/8 in ribbon for each tree.They are cut into 3 1/2 in. strips,made into a roll and pinned into a 6 in styrofoam balls.I used 2 straight pins for each roll of ribbon.It took about 750 pins.
I made a hole in the base of the ball for a wooden dowel and used hot glue to hold it in place.

The topiaries would have been more stable with foam in the base but then the laundry bag wouldn’t fit.