Hi Jim. Interesting thread.

I grew Tarbais here in the PNW and found that it had to be started in pots to reliably make mature seed. The vines seemed to want to climb on the neighboring trellis instead of their own and they made tanged masses 2-1/2 feet each side of the trellis before they climbed.

Interesting that the Rancho Gordo people think it is a runner bean. Baker Creek lists it as a common bean and I agree with them. - Dick