Rhubarb is technically a vegetable, only the stalk of the rhubarb, called ‘petioles,’ are edible.
Selection and Storage: The first rhubarb stalks to appear in early spring are the most tender. Stalks can range in color from pink to red to green; color is no indicator of maturity, though generally red stalks are sweeter than others. Firm, upright, thin, crisp stalks have the best texture. Wrap in plastic and refrigerate for up to one week.
Culinary Uses: Rhubarb is often dubbed the “pie plant,” and the stalks, soft and delectable when baked, do make a divine pie filling. But pie is by no means the only way to experience rhubarb. It’s delicious in all kinds of desserts, and this tart vegetable also works well in savory dishes.
Information from: The Produce Bible by Leanne Kitchen