Land artists take naturally occurring materials in the wild and rearrange them into works of art. That's what Richard Shilling does, using no glue, string, or any other materials. You can see some prime examples of his ingenuity at the link. Shilling makes excellent use of translucent leaves, flexible stems, and stones to make effective sculptures. The wind often sweeps away his works within minutes of completion, but that's okay with Shilling because it is an affirmation of the transient nature of life.
Link | Artist's Website
If that link doesn't work, just do a Google Image search (or search engine of your choice, I presume) for Andy Goldsworthy
Also information about him on Wikipedia.