They're called pot tubers & are grown only in pots- mainly to get cuttings from them. Most growers in England grow only pot tubers- they call the tubers we plant "chicken legs"! You can plant them in the garden in their pots & get a normal sized plant from them. Then you just lift the pot in the fall & store it- most people say to store on their side as that lets them drain if they're wet- the next year you take cuttings from them & start all over again. They really don't rot any more than regular tubers do & sometimes they break open the pots & grow out of them.