How to grow Scarlet Runner Bean
Updated October 2026
Scarlet runner bean is a fast, vigorous climber from the highlands of Central America, grown for its bright red flowers, which hummingbirds love, and for its edible pods and big, speckled dry beans. It climbs 10 feet or more in a season. It likes cool to warm summers and stops setting pods in heat above about 90°F, so it suits the northern half of the country and coastal California best.
📖 Our full guide: How to Grow Scarlet Runner Bean
Where to plant
Grow scarlet runners in full sun in rich, moist, well-drained soil, against a tall, sturdy support. They tolerate part shade well, which helps where summer afternoons are hot. Vines can reach 12 to 15 feet, so give them a strong frame such as a tepee, an arbor or netting on posts.
The plants dislike hot weather and generally stop setting pods when temperatures go above about 90°F. Flowers keep coming, and pods set again when the weather cools.
- Pacific Northwest, Northeast, Midwest, Northern Plains and Mountain West: sow in May or June after the last frost. Cool summers here suit runner beans well.
- Mid-Atlantic, Mid-South, Southern Plains and Northern California: sow early, just after the last frost, so the vines flower before the summer heat.
- Southern California: sow in late winter or spring so the vines flower in the mild coastal early summer; inland heat makes the flowers drop.
- Hawaii: best in cooler upland gardens.
- Alaska: sow in June once the soil is warm, or start indoors in pots.
- Florida, the Gulf South, Texas and the Desert Southwest: flowers drop in the heat and few pods set; grow them as a flowering vine if you like.
How to plant
- Put the support in place before sowing.
- Wait until the soil is about 60°F; seed rots in cold, wet soil.
- Sow seed about 1 1/2 inches deep, 6 to 8 inches apart along the base of the support.
- Guide young vines onto the support; they twine on their own once started.
- Mulch to keep the soil cool and moist.
Watering and feeding
Keep the soil evenly moist, especially once flowering starts. Dry soil makes the flowers drop and pods tough. Water at the base rather than over the leaves.
Beans fix their own nitrogen, so they need little fertilizer; compost dug in before sowing is enough. Too much nitrogen gives leaves instead of pods.
Harvesting
Pick pods young, while they are smooth, snap crisply and are less than about 5 inches long, before the beans inside swell and the pods turn stringy. Pick every few days to keep the vines flowering.
For dry beans, leave pods on the vine until they are dry and papery, then shell them and dry the beans fully before storing in a sealed jar. The flowers are edible too.
Using it
Slice young pods and steam or stir-fry them like green beans. Cook the large dry beans thoroughly, as with all dry beans, before eating. Never eat raw or undercooked dry beans.
Propagation and saving seed
Scarlet runner is a perennial with a tuberous root in frost-free climates, but it is grown as an annual in most of the US. Save seed from dry pods; it comes true unless other runner beans grow nearby.
Companion planting
Runner beans make a quick screen or a pollinator feature, and they are an easy partner for corn and salad crops.
Good companions
- Sweet Corn Strong corn stalks can carry the vines, and both suit a warm, sunny bed.
- Lettuce Grows in the light shade at the foot of the trellis through summer.
- Radish A fast crop sown along the row while the beans establish.
- Marigold Brings hoverflies and other beneficial insects into the bean patch.
- Corn
Keep apart
Avoid planting these close to scarlet runner bean.
Pests and diseases
Runner beans share the pests of other beans. Heat-related flower drop is often mistaken for a pest problem.
Pests to watch for
- Aphids Clusters of black or green insects on shoot tips and flower stems.
- Mexican bean beetle Copper beetles with black spots and fuzzy yellow larvae that skeletonize leaves from below.
- Spider mites Fine yellow speckling and webbing under leaves in hot, dry weather.
Diseases to watch for
- Rust Small rusty-brown pustules on the undersides of leaves late in the season.
- Halo blight Small water-soaked leaf spots surrounded by a yellow halo in cool, wet weather; do not save seed from affected plants.
Common questions
Why are my scarlet runner flowers falling off without beans?
Heat is the most common cause. Runner beans stop setting pods above about 90°F. Dry soil also makes flowers drop. Keep the soil moist and mulched, and pods will set again when the weather cools.
Can you eat scarlet runner beans?
Yes. Young pods are eaten like green beans, the large dry beans are cooked like other dry beans, and the flowers are edible. Always cook dry beans thoroughly.
Do scarlet runner beans attract hummingbirds?
Yes. The bright red, tubular flowers are a favorite of hummingbirds, as well as bees.
How tall do scarlet runner beans grow?
They can reach 12 to 15 feet in a season, so give them a tall, strong trellis, tepee or netting.
When should I plant scarlet runner beans?
After the last frost once the soil reaches about 60°F. In hotter areas, sow as early as possible so they flower before summer heat. Choose your region at the top of the page for the months.
Are scarlet runner beans perennial?
In frost-free climates they can regrow from a tuberous root, but in most of the US they are grown as annuals and resown each spring.
Sources we checked: University of Illinois Extension: Scarlet runner bean; NC State Extension Plant Toolbox: Phaseolus coccineus; Seed Savers Exchange: Scarlet Runner bean.
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