This sunflower relative grows through the warm season, and produces abundant crunchy tubers for harvest in the winter. The tubers are one of the best sources of a carbohydrate called inulin, which is a long-chain fructose polysaccharide. Inulin is not well digested by humans, but passes into the lower intestines, where it feeds bacteria of the genera Lactobacillus and Bifidobacteria, two of the most important genera of beneficial human gut flora. The bacteria, in turn, help us in many ways. Feeding inulin to your gut flora can greatly improve absorption of cation minerals from plant sources, such as Calcium, Magnesium, and Iron.
The plants grow to about 7 feet tall, and are bushy and thick. If planted in a block, they can shade out weeds. They can form a quick visual screen or hedge. We have two varieties. Eric is more sparsely stemmed and has larger leaves. It doesn’t flower until late fall, and then it usually falls over. It goes dormant later, and has higher yields. Craig is densely stemmed and has small leaves. It flowers all Summer long, and remains erect even after dormancy, which comes earlier than the other type. Yields are a bit smaller.
Soil: Tolerates many soil types, but will probably grow best in rich garden soil.
Water: Tolerates very wet conditions. May not produce well in droughty areas without substantial irrigation, though they will probably survive.
Cold: Sprouts tolerate mild frosts.
Propagation: tubers or pieces of tubers. Tubers left in the ground are often consumed by voles or rot, and are unreliable, as a means of propagation, in Florida. Plant refrigerated tubers in late Feb. 1.5′-2′ apart.
Pests: Pests are usually minor. They include mealybugs, termites, and deer. Fence out deer, and use organic insecticides for the mealybugs. Discard termite infested tubers.
Other problems: Digging and cleaning the knobby tubers can be labor intensive. Tubers often exhibit stem-end rot, and may rot entirely if left in the ground for too long.
Harvesting, storage, and preparation: Harvest the tubers as soon as the stems turn brown. 5lbs/plant is a good yield. Store them refrigerated and sealed in plastic bags to prevent drying. Freezing probably also works. The tubers can be cleaned with a toothbrush under running water, and the stem-end rot trimmed off. They can be sliced or grated into salads and other raw preparations. They can be baked, fried, steamed, sautéed, mashed, and included in a wide variety of recipes.
Additional references: http://www.floridata.com/ref/h/heli_tub.cfm