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.