The Scarlet Runner Bean: sowing, growing and harvesting

Description and botany

Little known in France, the runner bean is nonetheless the third most cultivated bean species worldwide. In many South American or Mediterranean countries, people enjoy runner beans either as long green pods or in the dried form of its seeds.

Botanical illustration

A member of the Fabaceae family, Phaseolus coccineus boasts numerous varieties, all descended from a wild variety still found in the humid marshlands of northern Mexico. Indeed, Central America is where the runner bean originates, specifically from Honduras, Guatemala and Mexico. Archaeological excavations have uncovered seeds of the wild variety in Durango and Puebla, and in the caves of Tamaulipas in Mexico, where the Anahuac peoples gradually domesticated it.

The runner bean likely made its way to European soil in the 16th century, brought by the Spanish, much like our green beans (Phaseolus vulgaris). By the 18th century, it had become a staple in English gardens, adorning them with its strikingly colourful flowers. It’s this very vibrant red that attracts hummingbirds living in the deep valleys of Mexico’s mountains. An American ornithological site even lists runner beans among the plants most visited by hummingbirds. In our regions, we’ll have to make do with bumblebees, honeybees, carpenter bees and other pollinating insects that also appreciate runner bean flowers. These insects are responsible for pollination and, consequently, fruit production.

The runner bean is a perennial plant, grown as an annual in our climate due to its lack of hardiness. It features a tuberised taproot, similar to dahlia tubers. These fleshy roots are rich in starch (but also contain toxic substances) and are part of the diet of certain Central American ethnic groups.

This ornamental and edible plant has a climbing habit. Its voluble stems twist and twine around any support provided, whether a trellis, wire mesh, pergola or any type of fence. They can reach 4 metres in length, though 2.5 to 3 metres is more typical.

Its deciduous foliage is medium green. The alternate, trifoliate and ovate leaves end in a point (acuminate), resembling a heart shape. They display light-coloured veins. Some varieties feature slightly purplish foliage on the underside.

We’ve already mentioned it, but the flowering is remarkable and alone justifies inviting runner beans into your garden. From June to September, the plant becomes covered in clusters about twenty centimetres long, composed of papilionaceous flowers in bright scarlet red. Other varieties bloom in red and white, orange or white.

The flowers of runner beans can be scarlet red, orange or bicoloured

These flowers produce long edible green pods, flat at first, then swollen as they fill with seeds in two dehiscent valves, displaying various colours depending on the variety. White marbled with red, pink speckled with red, bronze, brown, violet-black… these seeds boast original colours.

But their uniqueness doesn’t end there, as these runner bean seeds are said to have hypogeous germination. Practically speaking, unlike common beans, during germination the cotyledons remain underground while the stem emerges, already topped with the first leaves. With common beans, the cotyledons emerge above ground, attached to the stem.

During germination, unlike common beans (right), the cotyledons remain underground.

The runner bean likely inherited this characteristic from its montane origins, at altitudes around 2000 to 3000 metres. Similarly, the seeds germinate at relatively low temperatures, around 15 to 17°C. It takes about 4 to 5 months for the seeds to reach ripeness.

The different varieties of runner beans

Red-flowering varieties

Bi-coloured flowering varieties

White-flowering varieties

Runner Bean Scarlet Emperor - Ferme de Sainte Marthe Seeds

This variety produces long stems of almost 4m with bright red flowers and purple-black speckled seeds. The pods reach 30cm. A very vigorous variety, perfectly suited to cooler climates.

• Flowering time June to September
• Height at maturity 3 m

See the product sheet

Runner Bean Prijswinner - Dutch Red

This runner bean variety bears long clusters of scarlet-red flowers and pods around 30cm long

• Flowering time June to August
• Height at maturity 4 m

See the product sheet

Runner Bean Enorma

Reaching 3m tall, this runner bean variety flowers in orange-red and produces pods 25 to 50cm long

• Flowering time June to September
• Height at maturity 3 m

See the product sheet

Runner Bean Spanish Bean St. Georg

This variety produces red and white flowers, flat pods nearly 30cm long, and brown seeds marbled with black

• Flowering time June to September
• Height at maturity 4 m

See the product sheet

Runner Bean Hestia

A dwarf variety with coral and white flowers, growing just 40-50cm tall. Despite its size, it produces delicious pods

• Flowering time June to September
• Height at maturity 45 cm

See the product sheet

Runner Bean Moonlight

This variety offers pretty white flowers along with very tender, sweet pods

• Flowering time June to September
• Height at maturity 4 m

See the product sheet

Sowing scarlet runner beans

Where to sow?

Spanish beans are not particularly demanding when it comes to growing conditions. A good, rich, well-drained garden soil is perfectly sufficient. However, they also tolerate cooler soils. The soil should be loosened and cleared of weeds and stones.

Spanish beans enjoy a sunny position except in regions with hot summers, where they will need partial shade. However, provide them with a sheltered spot away from winds.

When to sow?

Outdoors, Spanish beans can be sown once the risk of frost has passed – mid-May north of the Loire, or April further south. Native to the mountains of Central America, Spanish beans germinate at temperatures between 15 and 20°C.

You can also choose to sow indoors in regions with longer winters. Since Spanish beans have a fairly long growing cycle (around 90 to 100 days from sowing to harvesting immature pods), you can sow as early as March in a heated cold frame. Then, simply transplant once the frosts have ended.

How to sow?

Like other beans, Spanish beans are sown in clusters of 3 to 4 seeds, spaced 50 cm apart. If sowing in rows, leave at least 80 cm between each furrow. The seeds should be planted about 5 cm deep.

Keep the soil moist until germination, which occurs around ten days after sowing.

The care of runner beans

The priority for runner beans is providing supports if you’ve decided to grow them in the vegetable garden. You can also choose to let them climb along a trellis or over a pergola to shade a terrace. In any case, in the vegetable garden, supports are essential. Several solutions are available to spark your imagination: teepees or A-frames to amuse the children, using strings stretched between stakes, concrete reinforcing bars or bamboo canes, with trellis netting, or even chicken wire. The stems will easily twine around their supports.

There are countless ways to support runner beans

Watering should be regular during hot weather, especially when the flowers are developing into pods. Regular watering also prevents flower drop. To reduce watering needs, don’t hesitate to mulch. Similarly, hoeing should be done regularly.

Earthing up is also recommended when the young plants reach 15 to 20 cm.

While less susceptible to common bean diseases, runner beans may still suffer attacks from aphid colonies which can weaken the plant. Natural predators like ladybirds help manage infestations. Virginie also shares her secrets for identifying and treating aphids.

As for young plants, they’re highly sought after by slugs. Feel free to check out the 7 ways to effectively and naturally combat these voracious pests.

Good Companion Plants for Scarlet Runner Beans

As a Fabaceae, in the vegetable garden, the runner bean thrives alongside potatoes, beetroot, carrots, aubergines, sweetcorn and squashes. However, planting alliums (garlic, shallots, onions and leeks) nearby is not recommended, nor is planting peas.

If you’re growing runner beans purely for ornamental purposes, pair them with morning glories, sweet peas, corkscrew flowers (Phaseolus caracalla) or nasturtiums.

When combined with morning glories, sweet peas and nasturtiums, runner beans create a beautiful colourful display or can cover an unsightly wall.

The harvest and storage of runner beans

There are two periods for harvesting runner beans. The first occurs when the pods are formed in the same way as other beans. Depending on the variety, the pods are picked when they reach 15 to 20 cm in length. Harvest before the seeds form, as the pods quickly become stringy. As long as they are flat, the pods are excellent. When they grow larger, they can be cut into pieces for cooking.

If you harvest your beans regularly, the plant will be encouraged to produce new pods. These immature beans can be stored for 5 days in the refrigerator, or blanched and frozen.

Runner beans are harvested at the immature stage when they are still flat or dry.

About 4 to 5 months after sowing, around October, runner beans can also be harvested when the pod is dry. This yields beautifully coloured dried beans, often as large as a €2 coin.

Scarlet Runner Beans: From Garden to Plate

Scarlet runner beans can be eaten like other beans. Picked very young, they can be prepared like fillet beans or mangetout, steamed or cooked in water, then garnished with tomatoes, onions or garlic. When larger, cut them into sections for cooking. They can be stir-fried in a wok with parsley.

When dried, scarlet runner beans are used in soups, purées, or crushed with a Spanish-style tomato sauce. It’s recommended to soak them in water overnight to facilitate cooking.