Rhubarb leaf stepping stones add interest and texture to any path in your garden. The large leaves with their veins, texture and shape make the ideal form for creative stepping stones. Rhubarb (Rheum rhaponticum) grows in U.S. Department of Agriculture plant hardiness zones 3 to 8. The leaves of rhubarb contain oxalic acid, making them unsafe for human consumption but ideal for garden projects.
Stepping Stone Setup
Assemble all of your supplies in an outside area with plenty of room to work. Plan to make your stepping stones during temperate, dry weather so the fast-setting concrete mix hardens properly.
Prepare the Container
Pour play sand into a large plastic storage container to a depth of 3 inches. The container needs to hold your flattened rhubarb leaf with a few inches all the way around it to the edges. It also has to hold the sand, so choose a container at least 4 inches deep.
Start the Mold
Wet the sand to slightly dampen it. This helps it hold together better for creating a form. Place large plastic wrap or other very thin plastic sheeting over the sand. Put your rhubarb leaf top down on top of the plastic and spread it flat.
Create the Form
Push the leaf -- gently so it doesn’t tear -- into the sand. Move the sand with your hands until the leaf measures about 2 inches into the sand. This creates a form for your stepping stone.
Don the Protective Gear
Put on rubber gloves and a face mask. Getting the concrete mix out from under fingernails is a chore avoided by wearing the gloves. The concrete will send up dust when it is poured that you don't want to breathe.
Make the Mix
Measure about 8 to 12 cups of the mix into the bucket and slowly add water while mixing with the trowel. Mix and add water until it has a toothpaste-like consistency.
Make the Stone
Scoop the the mix onto the center of the leaf. After each scoop, spread it with your -- still gloved -- hands. Continue to scoop and spread, working your way to the outer edges of the leaf. Fill the sand form to the level of the surrounding sand.
Allow it to Set
Allow the rhubarb stepping stone to set for at least two days. Remove it from the mold and pull the leaf off of the stone.