I wish the pictures did it a bit more justice, but we drew and painted with "found colors" at the garden this week.
We wandered around the field and the garden, testing and rubbing, seeing what made bold colors. We borrowed a piece of a roasted beet from the group that was making salad for lunch and used that for painting - with real paintbrushes and some natural paintbrushes for some new textures.
This was a really successful activity with this group of six- to nine-year-olds. We could do this again and again, I think, looking for more colors and textures, and the children would probably return to their favorite color-making things to make their pictures more representational.
I can see this being a great way to shake things up with a daily sketchbook prompt and a choice to have during outdoor play. I'm also thinking about mapping a space by color, and using nature guides to match the color with the plant name. Possibilities, possibilities!
Hopefully you can get out and try it - it only takes a piece of paper!