One of my favorite, easy-to-grow, flowering vines is the scarlet runner bean (Phaseolus coccineus). This fast-growing vine is both colorful and useful. Its bright scarlet red flowers attract hummingbirds while parts of the plant are also edible. The plant is easily propagated by saving seeds. Easy, useful, and pretty all in onevining plant!
The scarlet runner bean is native to the mountains of Mexico and Central America. The runner bean is a perennial species, although it is usually treated as an annual. The plant has heart-shaped, bright green leaves with scarlet flowers. The mature seed pods are over 6 inches in length containing several 1-inch seeds in each pod. Even the seeds are pretty with their black and purple or pink speckles.
As with most vegetables, the scarlet runner bean prefers full sun and rich, well-irrigated soil. The seeds should be planted after the danger of frost has passed. Follow the instructions on the seed packet for planting, but generally the seeds should be planted 1-1.5 inches deep and 4-6 inches apart. Provide a support, such as a trellis, at the time of planting. The seeds will germinate in 7-21 days and need warm soil temperatures to sprout. The vine, which matures in about 65 days, can reach a height of 8-12 feet and width of 3-4 feet.
The runner bean pods can be harvested and consumed like green beans when the pods are small (3-4 inches) and very thin. Otherwise, they become too fibrous. The seeds are edible as well, but mature seeds should not be eaten raw. In large amounts, raw or undercooked runner bean seeds have low severity poisonous characteristics due to thelectinphytohaemagglutinin. This effect can be neutralized with thorough cooking; there are plenty of recipesonline. Unfortunately, the seeds lose their pretty color and turngrey when cooked.
It is easy to save the seeds to share with others or to grow the next year. Let some of the seed pods fully dry on the plant. The seed pods will turn light tan or brown and become brittle with the seeds rattling inside. Break open the seed pods and gather the seeds. Dry them in a cool, dark area and then store them in an airtight container. In my experience, the seeds are forgiving even if I forget to store them properly right away. They also can remain viable for several years.
There are several varieties of runner beans, although the standard Scarlet Runner Bean is the easiest to find. Other cultivars include ‘Painted Lady' with red and white flowers and ‘Sunset' with salmon-pink flower. ‘Hestia' is a dwarf bush variety. I'm looking forward to trying ‘Painted Lady' next year!