Yes, they will multiply just fine if you leave them alone, though it takes a few years. Some disturbance / division of the tubers will speed up the process greatly, like it does with wild stands of sunchokes. I'd dig a few up and divide them into 3 or 4 and replant. If you do the same every time you harvest in the future, the patch will grow larger and healthier every year.
wayne stephen wrote:I planted 25 or so tubers last year. They did fairly well . I am interested in this batch for stock not this years food. If I leave them where they are will they multiply or do I need to dig them up and replant? I have too many other projects right now. I have heard they become woodier as they stay in ground but I assume they will form better eating tubers if I replant later. Right now I am just interested in forming a huge patch then to become bigger patches. What results have you all had ?