The scarlet runner bean is an ornamental plant grown for its intense red flowers and decorative seeds. Though the pods are edible, they tend to be fibrous; in the U.S., it is grown solely for its ornamental value. Throughout the United Kingdom, however, the beans of this plant are eaten, and the flowers are overlooked. It belongs to the Fabaceae family of plants, scientific name Phaseolus coccineus. Scarlett runner bean is a tender perennial, but is commonly grown as an annual. Other names for this plant include Scarlet Conqueror, Mammoth, Red Giant, and Fire Bean.
These garden plants are very fast growers, often climbing 10 feet (3 m) or more in one growing season. The entire scarlet runner bean plant is showy and attractive, with large, tender heart shaped leaves growing up long twining stems. They will completely cover an arbor, trellis, or other means of support. The flowers are similar to sweet peas, blooming in clusters through the summer before turning into long, thin seed pods full of dark multicolored red beans. The taste has been compared to garbanzo beans and Lima beans when cooked, and the entire pods may be eaten as well.
Similar to most other pod plants, the scarlet runner bean needs to be planted in full sun to be productive. These beans quickly grow from seed, and can be planted directly in the garden after the danger of frost has passed. Seeds should be placed about 3 inches (7.6 m) apart to give the plants plenty of room to grow. Flowers will appear in just a few weeks, turning into bean pods after about seven weeks. If they are kept picked, the plants will continue to produce new flowers and beans for up to three weeks.
The roots of the scarlet runner bean plants can be dug up and stored in a cool place during winter, to be replanted the following spring. This is a lot of work, however; since the plants grow quickly, it is usually more efficient to simply start them from seed each year. The climbing plants do well when planted along a garden fence, which they will rapidly trail up, similar to morning glories. This makes picking the bean pods easier and with no bending required.
The flowers of the scarlet runner bean attract many types of bees to the garden as well as hummingbirds and butterflies. They are susceptible to damage from numerous harmful insects and are prone to fungal diseases in wet weather. In addition, deer and rabbits will completely destroy these plants if given the chance, so they should be planted in a protected area that these animals cannot access.