Common Name: Runner Bean

General Information

Phaseolus coccineus is a perennial climbing plant producing annual twining stems 3 - 7 metres tall from a tuberous rootstock. The stems scramble over the ground or climb into the surrounding vegetation. Dwarf, non-climbing forms growing around 60cm tall have been developed[].
Runner beans have been a cultivated food crop since at least 900 AD. They are commonly cultivated in both temperate and tropical areas of the world for their edible seeds and immature seedpods[]. The plant is also sometimes grown as an ornamental[].

Known Hazards

Large quantities of the raw mature seed are poisonous[, ]. The toxins play a role in protecting the plant from insect predation.

Botanical References

Range

Southern N. America - Mexico.

Habitat

In or around mostly mixed forests, often on steep slopes or along stream beds, open wooded grassy areas, or on edges of cloud forest; at elevations from 1,500 - 2,500 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial Climber
Height	3.00 m
Growth Rate	Fast
Pollinators	Bees
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental

Cultivation Details

The runner bean is a plant of higher elevations in the tropics, where it can be grown at elevations from 1,400 - 2,800 metres. It can also be grown at lower elevations in the subtropics and as an annual crop in the temperate zone. It grows best in areas where annual daytime temperatures are within the range 12 - 26°c, but can tolerate 5 - 30°c[]. When dormant, the plant can survive temperatures to just below freezing, but young growth can be severely damaged at 1°c[]. It prefers a mean annual rainfall in the range 800 - 1,500mm, but tolerates 400 - 2,600mm[].
Requires a warm sheltered sunny position in a rich well-drained soil with plenty of moisture in the growing season[, , , ]. Dislikes heavy, wet or acid soils[]. Soíls in the wild are often rocky, ranging from very sandy granitíc with mica to rocky limestone with lots of humus, and may be yellow, red or black. Plants are usually found in very moist locations[]. Prefers a pH in the range 5.5 - 7, tolerating 5 - 8.2[].
Plants commence flowering about 40 - 60 days after sowing the seed[].
Plants flower under long day conditions, which is ideal for temperate regions[].
Harvesting of the immature pods can commence around 3 months after sowing and can easily continue for 2 - 3 months[, ].
Mature seed can be harvested 4 - 5 months after sowing[].
When grown for their edible pods, the immature pods should be harvested regularly in order to promote extra flower production and therefore higher yields[].
In the UK, yields of green pods are reported to average 9 - 14 tonnes per hectare[].
In Kenya, yields of dry seeds from smallholder production have been estimated to be about 0.9 - 1.5 tonnes per hectare[].
Plants are perennials but are often grown as annuals, especially in the temperate zone. In the tropics the plants will crop for two to several years[].
There are many named varieties[]. Most varieties are climbing plants but some dwarf forms have been developed[].
The plants might need some protection from slugs since these creatures adore the young shoots in the spring[].
Runner beans grow well with carrots, cauliflowers, cucumbers, cabbage, leek and celeriac[, ]. They are inhibited by alliums and fennel growing nearby[, ].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Immature seedpods - raw or cooked[, , , ]. They have a pleasant mild flavour and are widely used as a vegetable in many areas of the world. They can be added to salads, cooked as a vegetable or added to soups, stews etc[]. The pods can be up to 40cm long[].

The immature seed is used like shelled beans as a vegetable[].

Mature seeds - cooked. A mild flavour with a floury texture[]. The protein-rich mature seeds can be dried and stored for future use. They need to be thoroughly cooked before being eaten in order to destroy a toxic principle. They are soaked for 12 hours prior to use and are eaten boiled or added to soups etc. The seed can also be ground into a powder and added to cereal flours for making protein-enriched bread etc[]. The oblong seed of wild forms are around 7mm long, 6mm wide and 6mm wide - cultivated seeds can be mucch larger, up to 25mm long[].

Flowers - raw. A bean-like taste[, ].

Young leaves - cooked and used as a potherb[, ].

Root - cooked[]. Rich in starch[]. Another report says that the root is poisonous[]. The tuberous root is edible, but it is fibrous and may contain toxic compounds - these can be removed by soaking or peeling and by discarding the cooking water[].

Medicinal

A root decoction is taken against malaria or applied to swollen eyes[].

Coccinin, a peptide isolated from the seed of scarlet runner bean, has shown antifungal activity against a range of fungi. It also inhibited proliferation in leukaemia cell lines and reduced the activity of HIV-1 reverse transcriptase[].

Agroforestry Uses:

In Kenya the plant is grown at elevations between 2,000 - 2,500 metres and is growing well in humid areas where it is often interplanted with maize[].

Other Uses

None known

Propagation

Pre-soak the seed for 12 hours in warm water and sow in mid spring in a greenhouse. Germination should take place within 10 days. When they are large enough to handle, prick the seedlings out into individual pots and plant them out after the last expected frosts.
The seed can also be sown in situ in late spring though it may not ripen its seed in a cool summer.