Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
One of my favorite flowers to grow in my vegetable garden is scarlet runner beans. They bloom profusely, attracting both hummingbirds and bees. Like most American gardeners, I grow them for their ornamental value. European gardeners ignore the flowers and grow them for their edible beans.
What are Scarlet Runner Beans?
Scarlet runner beans (Phaseolus coccineus) are a member of the bean family. They are native to the mountains of Mexico and Central America. The vines are adapted to grow at higher elevations than the rest of the bean family. After the Spanish invasion and colonization of Mesoamerica, the beans were introduced to Europe. They were subsequently brought to North America by European colonists.
The vines can grow to 15 feet long, but in colder areas usually only reach 6 to 8 feet in length. They are hardy in zones 7 – 11 but are usually grown as annuals. They grow from a tuber so in areas with mild winters, the vines will grow back each spring from the underground tuber. In colder areas, you can dig up the tuber in the fall and store it just as you would with dahlia tubers. You can plant them in your garden in the spring after the last frost when the soil reaches a temperature of 50⁰F. The vines that grow from tubers replanted in the spring will bloom sooner than vines grown from seed.
The tubers are edible. They are eaten by the native peoples living in Mexico and Central America.
The flowers are usually red but can also be white. They grow in sprays, similar to sweet peas. The flowers are edible and taste like beans. My favorite cultivar is called Painted Lady. It is an heirloom variety with bi-color flowers either red and pink or red and white. I prefer the red and white. If you don’t plan on eating the beans, remove the pods to keep the vines blooming.
The pods are edible when young. They become tough as they mature. The beans are black with purple mottling unless you are growing vines with white flowers, in which case the beans will be white. The beans can be eaten fresh or dried. If you elect to dry them, be sure to soak them for 6 to 8 hours before cooking them. The dried beans taste like chestnuts.
How to Grow Scarlet Runner Beans
Scarlet runner beans need full sun and rich, well-drained soil. Keep your vines well-watered, at least 1 inch of water each week. A thick layer of mulch will help keep the soil moist between waterings.
Be careful not to over fertilize. Too much fertilizer will result in long vines and lush foliage but few flowers and beans. A balanced fertilizer such as 10-10-10 is best.
The vines climb by twining around whatever is close by. They are usually grown on teepees, but a trellis or fence works just as well. The vines grow quickly so they make an excellent privacy screen during the growing season.
How to Grow Scarlet Runner Beans From Seed
Scarlet runner beans are a great project for a child’s garden. The seeds (actually the beans) are big enough to be easily planted by small fingers. They germinate quickly and grow quickly to the delight of the young gardener.
The beans can be direct sown in your garden (or your child’s garden) after your last frost when the soil has warmed to 50⁰F. Most gardeners grow them on a teepee that is constructed from 6 to 8 poles. You will need very long poles because each pole should be at least 3 feet away from the other poles. Plant your seeds in a circle around each pole, 6 inches away from the pole and 6 inches apart. Plant them 2 to 3 inches deep. It doesn’t matter which way you plant them. There is no top or bottom. Germination should occur in 1 to 2 weeks.
You can also start your seeds indoors 4 weeks before your last frost. Plant the seeds 2 to 3 inches deep in a container. Keep the soil moist. Germination should occur in 1 to 2 weeks. You can plant your seedlings in your garden after all danger of frost has passed and the soil has warmed to 50⁰F. Be sure to install your teepee before your plant your seedlings. If you try to install your teepee after you plant your seedlings, you will risk injuring or killing them.
How to Save Seed From Scarlet Runner Beans
I don’t have a basement so I can’t winter over the scarlet runner bean tubers from my garden. I save the seed instead. Scarlet runner beans will cross pollinate with other beans so you can only grow them and no other type of bean if you want to save seed.
To save the seed, allow the pods to dry on the vine. The pods will be ready when they are brown and the beans are rattling around inside. If there is a frost in the forecast and your pods aren’t quite dry, you can harvest them and bring them indoors to finish drying.
Store the beans in a cool, dark place until you are ready to plant them the following spring. I store my seeds in one of the crisper drawers in my refrigerator.
© 2019 Caren White
Rebecca Mealey from Northeastern Georgia, USA on December 18, 2019:
Those are so pretty! I've never heard of scarlet runner beans.Interesting! Thanks for sharing!