Rhubarb—Rheum rhabarbarum L.1
Rhubarb is a perennial plant that forms large fleshy rhizomes and large leaves. The thick succulent leafstalks (petioles) having attractive red color are the edible parts. The rhizomes and crown persist for many years in areas where rhubarb can be grown. Leaf blades are up to 1 foot or more in width and length. Petioles are up to 18 inches long, 1–2 inches in diameter, and generally somewhat hemispherical in cross section.
Rhubarb, the "pie plant," is a very successfully grown and popular perennial vegetable in many parts of the country, but is not well adapted to Florida. It does not thrive and is rarely grown where the summer mean temperature is much above 75°F and the winter mean is much above 40°F. Thus, Florida gardeners should not expect much luck with this crop as a perennial, as both our summers and winters are warmer than this.
In Florida, we have no periods cool enough to send the crowns into rest period; therefore, the plant continues to grow through the winter to a certain extent. Upon the arrival of spring when we would expect an abundant flourish of leafstalks, we find only a continuance of the old growth.
Seeds are easier to obtain then crowns, but plants arising from seeds show a great deal of variation in color and form. However, it is possible to sow seeds in a seedbed or seed flat and select the most uniform and desirable plants to set in the garden. It is questionable whether or not sufficient growth can be obtained in 1 year following planting for this method to be practical.
Rhubarb should be grown in Florida as an annual, either from seed or from crowns. If from crowns, three methods are possible:
crowns may be purchased from northern seed companies as early in the spring as is possible to obtain crowns whose rest periods have been broken;
crowns may be obtained from the north in late summer, placed in cold storage (freeze them solid for 6 weeks) to fulfill rest requirements, and planted in the fall or early winter; and
winter forcing is another method using crowns. This method is a common commercial practice in the north, and may be of some value to home gardeners in Florida.
Roots that are 2–3 years old and have had a rest period are placed under more or less artificial conditions where they will sprout and produce stalks.
In South Florida, where temperatures seldom drop below 32°F (rhubarb will withstand temperatures down to this), seed might be planted in September in a seed flat and transplanted in the garden in October. Harvest could begin by about February. In a trial at Zellwood, on muck soil, seeds planted December 12 produced marketable petioles by May 26.
'Victoria' is an old variety that produces large but poorly colored stalks. Burgess 'Colossal' is large but produces pale green stalks. Popular red-stalked varieties are 'Canada Red,' 'MacDonald,' and 'Ruby,' but their adaptability to Florida is uncertain.