Overwintered runner beans (Phaseolus coccineus)

[Diane Whitehead]

I read that runner beans can be perennials because they form a tuber which overwinters and then grows in the spring.  I've never noticed this happening in the garden, but maybe it would have if I didn't always dig the garden before sowing seeds.

Last year I decided to experiment.  I grew several kinds of runner beans in large pots in my unheated but frost-free greenhouse.  It is mid May, time to sow bean seeds out in the garden. I just checked the greenhouse and I have very tall vines - much taller than me, and flower buds have formed but haven't opened yet.  I wasn't paying attention, so I don't know when they started to grow.

I wonder if they will become truly perennial and carry on next year too.

[Tarruvi]

I just checked the greenhouse and I have very tall vines - much taller than me, and flower buds have formed but haven't opened yet.  I wasn't paying attention, so I don't know when they started to grow.

I wonder if they will become truly perennial and carry on next year too.

This has me thinking, this could be another very handy application for a hands-off type of gardening. Say you have a spot in the garden you aren't too interested in, but you plant runner beans there and you're set for however long the plants hold out for.

I think an offshoot of this, is using the runner bean's ability to make tubers and crossing them with other bean varieties to have them appear year after year. Like a rose garden coming to life every year, except they're all kinds of beans.

[Tim DH]

Hi Diane,
     The problem with Runner Beans in a greenhouse is that they need insect pollination. So you could end up with luscious growth, early flowers and no beans!

[Diane Whitehead]

I took the place of the insects to pollinate the flowers - I pushed the keel down a bit.

[Carol Deppe]

Here in maritime Corvallis Oregon, runner beans in an area that is not tilled in fall will overwinter most winters. (The ground does not usually freeze more than an inch or two deep. The roots are usually below that.) However, the overwintered plants didn't give beans any earlier than those planted from seed in spring. They weren't as productive as the same space planted from seed in spring, either.