Growing Guide: Scarlet Runner Beans
Download: Scarlet Runner Beans Growing Guide
Sometimes simply called “scarlet runners,” these plants have so many diverse benefits that they should be on must-have plant lists at every school, community, and home garden that has room for the vigorous vines!
Scarlet runner beans, Phaseolus coccineus, are in the same genus as garden beans, Phaseolus vulgaris. The species name coccineus is derived from Latin word for red and refers to the plant’s brilliant flowers. (The species name for garden beans, vulgaris, is Latin for “common.”) (Want to know more about botanical classification? Check out What's In a Name?)
About Scarlet Runner Beans
In the U.S. scarlet runner beans are most often grown as ornamentals and are thus usually found in the flower section of catalogs and websites. In the U.K., however, the plants are prized for their edible harvest and are listed alongside green beans.
The plant is native to the mountains of Mexico and Central America and has been domesticated for more than 2000 years by the native peoples there. They consume most parts of the plant, including the starchy, tuberous roots.
When you observe most bean seeds germinate, you’ll see the stem rise from the soil, carrying with it the seed leaves (cotyledons). Then the first true leaves emerge from between them. The cotyledons of scarlet runner beans remain underground.
Scarlet runner beans produce vigorous vines that can reach up to 15’ and require a very sturdy support structure. Their vines twine clockwise around a support when viewed from above. Most other kinds of beans twine counterclockwise as they climb.
The abundance of red flowers makes the vines magnets for hummingbirds and bees. This prolific blooming also hints at the plants’ potential for yielding a generous, season-long harvest of edible beans. Scarlet runners are considered by some to be one of the highest-yielding types of beans.
Runners, Half-Runners, and Pole Beans
Are runner beans the same as pole beans? Although both produce long vines, the term “runner bean” refers exclusively to the species Phaseolus coccineus. (Oddly, the term “half-runner bean” most often refers to pole bean varieties, Phaseolus vulgaris, with relatively short vines. One might wonder why they aren’t called “half-pole” beans.)
Scarlet runner beans are used in many cuisines worldwide. Harvested as green beans, they’re a popular side vegetable in British cuisine. And specific varieties are grown for drying and prepared in signature dishes in Spain and Greece.
Plant parts are edible at nearly all stages of growth:
- The striking scarlet flowers are edible, with a mild, sweet, somewhat “beany” flavor. Use in salads and to garnish soup and other dishes.
- Immature pods can be harvested before they become fibrous, and then steamed and eaten as you would any green bean. The pods have a rougher surface texture than we’re accustomed to.
- Let the pods grow a bit longer so the light pink seeds plump up inside them. Then shell them, cook, and eat as you would lima beans.
- Allow the seeds to fully mature and dry inside the pods, then shell them and store them for use in winter soups.
Convinced to give them a try?
Step-by-Step Planting Instructions
- Choose a spot in full sun with rich, moist soil that has been amended with compost.
- Although the seeds will germinate in soil that’s slightly cooler than many other types of beans (50 degrees F.), the foliage won’t tolerate frost. Wait until after your average last spring frost date has passed and the weather has settled.
- Erect a sturdy support for the plants.
- Direct-sow the seeds around the support, placing the seeds 2–3” deep in the soil and spacing them 4–6” apart. Seeds should germinate in one to two weeks.
- Plants grow vigorously and require regular watering, especially once they begin flowering. A layer of organic mulch, such as straw, shredded leaves, or pine straw, will help retain moisture. Keep the mulch an inch away from plant stems to prevent rot.
- Begin harvesting at any stage, described above. The plant’s flower and bean production may slow in the heat of midsummer, but will pick up again as the weather cools.
- At the end of the season you have several options, depending on your climate and preferences.
- Save seed for replanting. Leave some pods on the plant until they’re completely dry and the seeds rattle inside. However, if a hard frost threatens, bring the pods indoors to finish drying. Then store in a cool, dry, dark place. Dig up and compost the rest of the plant remains.
- Dig up the tuberous roots for replanting. Similar to dahlias, you can dig up the roots and store them in damp sand in a place that stays cool but not freezing. The plants will re-grow quickly once the roots are replanted in spring.
- Leave tuberous roots in the ground. In regions with moderate winters, cut back the vines and mulch over the roots to protect them from freezing.