Well, now, I used to do this with my Cub Scout dens. They would choose weeds, flowers, ferns, colored fall leaves and I'd give them a 10 or 12 inch bit of unbleached muslin that I'd washed and prepared with a hem on one end to be able to hang it on the wall.
They got a lot of energy and aggression out with the hammers and the muslin. They made up their own pictures or scenes that pleased their eye and the parents that made them. I've washed mine, that I made as an example, and the dyes didn't wash out. It's still beautiful but I know there are finishing products that can be put on fabrics to keep the dyes pure......just don't remember what they are.
However, you've just put another idea in my many quilt notebooks. Will I live long enough to get to all the quilt ideas????
Sharon