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This is so seldom done, we'reThis is so seldom done, we're going to suggest this: Dig them with a fair bit of soil around the tubers and as little disturbance to the roots as you can manage, and put them into suitably large pots. If the flowers are mature or just past that stage, clip them. As you no doubt know, tubers should be lifted in fall, so you will have that part done. After the first frost, prepare them as usuall for the winter respite. Plant as usual next year.