What are the methods of rhubarb preserving that will help to store this versatile vegetable year around? Rhubarb is a vegetable but is often thought to be a fruit. It is mostly used in sweet applications but can also be a savory addition. It has a short season, only blushing during the spring in most regions. So can you freeze fresh rhubarb? Learn how to preserve rhubarb and enjoy the tart goodness of this gorgeous vegetable even in winter.