It crops over a long period, is completely hardy and grows in any garden soil. Rhubarb grown in hothouses (heated greenhouses) is called hothouse rhubarb, and is typically made available at consumer markets in early spring, before outdoor cultivated rhubarb is available. In the United States rhubarb generally, will grow quite successfully between from Maine to Illinois, and west to Washington. When to plant rhubarb If you live in the Southern States of the United States, rhubarb … Budded pieces, meanwhile, are a portion of an established crown. Rhubarb is grown in many areas. Most of the commercial rhubarb grown in the United States is grown in Washington, Oregon and Michigan. With greenhouse production, it is available throughout much of the year. These can be cropped two years after planting. Rhubarb crowns are established plants that are at least one year old. Rhubarb is a rhizomatous perennial whose leafstalks (technically leaf petioles but often referred to as ‘sticks’ or 'stems') are grown as a vegetable but used mainly as a dessert. They will produce a crop in the first harvest season after planting, which is much sooner than rhubarb plants that are grown from seed.