Phaseolus coccineus Seeds | Scarlet Runner Bean

Scarlet Runner Bean (Phaseolus coccineus) twining up supports with sprays of scarlet flowers and green pods — Scarlet Runner Bean (*Phaseolus coccineus*): Fabaceae, a twining bean of Central American mountains, grown for pods, beans and scarlet flowers.

LATIN NAME: Phaseolus coccineus

COMMON NAME: Scarlet Runner Bean

Plant Profile

Scarlet Runner Bean is a strong twining climber of the Central American highlands, running three to four metres up any support in a single summer. It carries large heart-shaped leaves and, from midsummer onward, generous sprays of vivid scarlet flowers that pull in bees and hummingbirds, followed by long green pods of plump beans mottled purple and black when dry.

Unlike the common bean it tolerates cool summers, and in mild climates the tuberous root survives winter underground and resprouts as a genuine perennial. Young pods are eaten as green beans, the dried beans are hearty in soups, and the flowers are edible and decorative.

Science & Biotechnology

The species is a standard subject in pollination and crop research, its bird-pollinated flowers making it a useful contrast to the bee-pollinated common bean, and its cool tolerance has been studied as a trait to bring into Phaseolus breeding.

Centuries of cultivation in Europe since the sixteenth century have left a detailed record of its behaviour, and its perennial tuber habit has been examined as a survival strategy unusual among the cultivated beans. Research on its tuberous roots has shown they carry the season’s restart in mild climates, and trials of runner bean breeding lines have examined cool-summer yield as a heritable trait. The species’ chromosomal makeup, a tetraploid relative of the common bean, has featured in studies of how the crop beans evolved, and its wild highland populations remain a source of breeding material.

Uses & Benefits

It does three jobs in one: a bean crop for cool summers, a screen of scarlet flowers on any fence or teepee, and a soil-building legume. The dried beans, rich in starch and protein, keep well, and the flowers and young pods carry the kitchen value through the season.

Common beans are slow-starch protein staples linked in population studies to heart and metabolic health, and the runner bean shares that profile, its pods adding fibre and its seeds resistant starch. In Britain it remains one of the most popular garden beans, and allotment traditions hold that a row of runners at the north edge of a plot shades neither neighbour nor crop. The flowers are edible too, tossed into salads for colour, though most gardeners leave them for the bees and the crop; both uses come from the same spray.

Growing from Seed

Sow the big seeds an inch deep into a fine, free-draining compost after the last frost, one or two to a pot, and keep them just moist in good light; emergence takes a week or two in warmth.

Set the plants out against a sturdy support in full sun, water through dry spells, and pick pods regularly to keep the crop coming. In mild areas leave the roots in the ground under mulch and the plant returns in spring. Pick the pods young and often; once the seeds swell inside, the plant turns its energy to seed and the crop tails off until the dried-bean stage. Feed lightly at planting and again at first flower; too much nitrogen gives leaf at the expense of pod, a balance the species makes obvious within a season.

Our Take

A climber that earns its space three times over: scarlet flowers for the season, green pods for the kitchen, and beans for the winter pot.

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