Grab a small plastic bag from some store. This one was about 12" high and 8" across.
Tear or cut pieces of tissue paper into small squares. And glue on, overlapping and scrunching them up.
Use some multi-colored brags to add color and to keep the paper down. I used about 20 brags on each side.
This is what your bag looks like done. You can see how it also looks like a Christmas Tree. But I was going for a spring grass and flowers vibe!