I hate to admit that I have never paid attention to the growth of the rhubarb before this year. Rhubarb leaves are produced underground. The leaf is poisonous so that the bugs in the ground don't eat it. The plant then only has to produce the stem during the summer. Early in the spring, the rhubarb plant sends a red, fleshy knob out through the soil into the sun. This knob contains a leaf that is all folded up. The leaf breaks out of the covering and unfolds in the sun. The larger the leaf grows, the smooth the surface becomes. The folds are fascinating to look at.