flowerbug
Garden Master
Not as easy as it sounds. The roots may indeed winter over where the ground does not freeze; but they are not as substantial as bulbs, and delicate. I noticed that my Aeron Purple Star roots a couple years ago were noticeably large, so tried to lift & winter over some of them. Although the area below the stem was swollen, many of the larger roots were very fragile & broke off easily during extraction.
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Despite my best efforts, those roots did not survive my long winters. In retrospect, had I planted them in pots mid-Winter, they might have survived... I may try that one of these years. The roots also might have better chances of survival where the ground is only frozen for a short period; but chances are that most of those areas would also be too hot to grow runner beans successfully.
i've never seen pictures of those before! neato! never found any roots that looked like that on any of the pole beans here.