You can make your stepping-stones from a Banana plants, ficus, and Elephant Ear Palms. Rhubarb leaves work well, too. Use any large leaf whose pattern you love. You can find them at your local nursery or home and garden store.
Lay cardboard flat in order to protect your work surface. You can also use plastic sheeting, if you prefer. We used cardboard. Put the leaf in the center of the cardboard, vein-side up.
Mix the concrete to a stiff consistency, following package instructions. It should be the consistency of brownie batter. Or you can buy it pre-mixed!
With gloved hands or a trowel, move concrete onto the center of the leaf, spreading it almost to the edge of the leaf to a thickness of approximately 2-INCHES; press firmly to eliminate air bubbles.
Allow it to cure for at least an hour, then lift the stepping-stone from the cardboard and turn it over to see the walking surface. Smooth any rough edges or spots where the concrete may have spilled over. The natural moisture in the leaf should allow it to come off the concrete easily.
If residual leaf remains on the concrete, spray with water and the leaf should come right off.
After 2 hours smooth your edges and pick out any concrete that may have spread over the leaf edges. Let it cure for 24 - 48 hours before putting it out into your yard or garden.
Make sure the surface that you lay your stepping-stones on is flat. Clear away any debris.