Trim the rhubarb stalks. Remove and discard the leaves. Wash the stalks under cold running water and scrub off any stuck dirt. Pat the stalks dry.
Slice the rhubarb into ½-inch thick pieces. Spread the pieces out in a single layer on a baking sheet or freezer-safe tray. Place the tray in the freezer, somewhere it won't get bumped, until the pieces are frozen solid. This usually takes about 1 to 2 hours.
Transfer the frozen pieces to a freezer bag or container, seal tightly, and label. Store in the freezer for up to a year.
Add frozen rhubarb directly to recipes for cooked preparations and baked goods. You don't need to defrost it first. Don't use frozen rhubarb in recipes where it's served raw, since it can get soggy.