I used small twigs from my yard and using a hot glue gun, I added them a layer at a time until the entire frame was covered. Then I covered with a light coat of Mod Podge to seal it. Also, look at the little flower pot done to match. This was a small tin can covered in twigs.
Uses for old wooden frames that are missing glass. These tips are from the ThriftyFun community. Decorate a picture frame using paint and found objects.