There are both red & purple yardlongs. Chinese Red Noodle (the most popular red cultivar) has a longer DTM than some of the black seeded cultivars, but still does well here.

I tried a purple-podded yardlong (from an SSE member in the deep South) and it appeared to be daylength sensitive, with no flowers before September. The few pods which did form before frost, though, were dark purple, not red; so I know both colors exist.

Thanks! My purple started blooming here a couple of weeks ago. If the weather holds up I should get a fair crop.

I have a regular green yearlong variety growing (in 9A) and started getting the beans (3-4 beans every 2 days). The seed color is red, though. Super crunchy and tasty. :)

There are green, burgandy, and purple yard long beans. Each color bean even has different colored seeds, black, reddish, other. The beans are a type of cowpea and can be dried and eaten as well, instead of the fresh bean.