‘Black Knight’ Heirloom Runner Bean Seeds

‘Black Knight’ is a seed vegetable, commonly called runner bean or scarlet runner bean. A prized British heirloom from the 1800s, ‘Black Knight’ was originally grown by Edmund Knight, Bishop of Shrewsbury. This handsome climbing vine is valued not only for bean production but also for ornamental purposes and can fit beautifully into an edible landscape. Selected from Scarlet Runner, ‘Black Knight’ sets loose clusters of scarlet-red pea-like buds along its vines that open into showy flowers. Masses of smooth, attractive solid black pods follow the flowers. Completely stringless and delicious when young, the pods are edible, if cooked, but should be picked early, before the seeds (beans) swell appreciably in the pods. Each pod contains 6 to 10 bright pink beans, which turn brown as they dry. The beans can be eaten fresh or dried. The flowers are also edible, having a bean-like flavor, and can be used in salads or as garnish. They are highly attractive to hummingbirds, butterflies, and bumble bees.

Typically grown as an annual, ‘Black Knight’, an herbaceous short-lived perennial (Zones 7-11), is a member of the legume family (Leguminosae or Fabaceae). ‘Black Knight’ is a vigorous, robust indeterminate variety, growing vertically as a graceful flowering vine that requires support, such as our bean growing tower or natural bamboo ring set. Although the vine may be allowed to trail along the ground, growing it vertically creates height and dimension in the garden and uses space efficiently, making it a great option for small gardens.

Runner beans are typically the most productive of all the beans, with each plant producing about 2 pounds of beans, in ideal conditions. For the best yields, pick pods promptly, which encourages the plants to set more. Fewer pods will be set in hot temperatures (around or above 90°F), but flowering is usually abundant in hot summer climates.

Easy to grow and adaptable, ‘Black Knight’ prefers a sunny location with fertile, organically rich, moist, well-draining loam, having a pH of 5.5 to 7.0. Water the plants liberally during flowering and fruiting, but do not fertilize heavily, unless lush foliage is preferred over flower and bean production.

Nitrogen-fixing plants, beans naturally improve the soil in which they are planted by taking nitrogen from the air and converting it into a usable form in the soil.

Open pollinated, this heirloom plant produces seed that will grow true to variety; however, runner beans readily cross-pollinate, so heirloom varieties should be isolated if true seed is desired.

A warm-season vegetable, sensitive to cold temperatures and frost, runner bean seeds can be direct sown into warm spring soil (at least 50°F) after the last frost date. For an earlier harvest, seeds can be started indoors 4 to 6 weeks before the last frost date in spring and transplanted after all threat of frost has passed. Flowers begin to set fruit with night temperatures between 55 and 75°F. Protect plants with row covers if temperatures are expected to dip below 50°F. Mulching helps to moderate soil temperature as well as to maintain soil moisture and control weeds. Succession plant every two weeks to ensure a continual harvest.