The vine can grow to two meters or more in length, the green
pods are edible whole before they become fibrous, and the seeds
can be used fresh or as dried beans. The starchy roots are still
eaten by Central American Indians. In the UK, the flowers are
often ignored, or treated as an attractive bonus to cultivating
the plant for the beans, whereas in the US the scarlet runner is
widely grown for its attractive flowers by people who would
never think of eating it. The flower is known as a favourite of
Hummingbirds. Runner beans contain traces of the poisonous
lectin, Phytohaemagglutinin, found in common beans and hence
must be thoroughly cooked before consumption.