Here is a fun and creative garden project. Start your project on a sturdy table or on the ground. Lay a trash bag out and make a pile of sand as large as the leaf that you will be casting. Clean play sand works the best. (you can use it in the garden after you are done). Select a LARGE leaf with deep veins for the casting. This casting is rhubarb. Hosta leaves and Gunnera leaves can also be used.
Put a piece a plastic wrap over the sand pile that you just made. Using "Mortar" mix cement, add water till it is thick like a brownie mix. Spread it over the leaf, thinner on the edges and thicker in the middle. Use disposable gloves to protect your hands from the cement.
After you cover the entire leaf, cover it with another piece of plastic wrap. Let it dry for about 24 hours. Remove the plastic after it dries and turn the casting upside down. It is heavy.
Use a scrub brush and water to remove what is left of the leaf.