Bean: Runner Bean 'Mergoles'

Runner Bean ‘Mergoles' is similar to the famous red scarlet runner, but with decorative clear white blooms. The beans are cream coloured, similar to cannellini beans and are plump, with a shape almost like a half moon. They are also known as sweet white runner beans. This high quality variety sets well in almost all conditions and produces abundant yields of delicious, stringless, fleshy pods.

The smooth, long green bean pods can be eaten fresh or frozen, or left on the plants to mature and harvest the mature creamy white seeds. They have a pleasing texture and hold their shape well and are considered excellent for use in soups and salads.
This is a vigorous variety with prolific yields of long, pods with good flavour. With a high crop to space ratio, it will produce through the summer heat and is better able to withstand adverse weather conditions. The plants show resistance to Bean Common Mosaic Virus.

The plants make a beautiful show, with the flowers continuing for most of the season. Its good looks mean that it looks at home in the flower garden as well as the vegetable patch and are ideal for smaller gardens where space is at a premium. The plants grow to a height of around 2m (6ft) and with a spread of 30cm (12in) so support from canes or netting is recommended.
Traditionally used as a soup bean, the pods can be picked young and eaten fresh when juicy and tender. The cream coloured dried beans and the white flowers are also edible, which makes it showier in edible flower dishes.
Harvest July to October, the top quality long, fleshy pods not only taste delicious but also freeze well. 80 days to maturity.

Runner Beans and their flowers are an 'Edimental' - the plants that are edible and ornamental and are grown for both the flowers and the sweet pods. The edible flowers are especially showy in salads and, surprisingly enough, taste of beans.
The magnificent slender clusters of runner bean flowers, (available in red, white and pink flowering varieties), are pretty enough for the flower garden if other space is limited, where the plants can grow up trellis and pergolas.

Position:
Beans prefer to grow in moist, fertile soil in a sunny, sheltered spot away from strong winds. Prepare the soil for planting by digging over and adding plenty of organic material, this will help to improve the soil's moisture-retaining ability and fertility. Beans can also be grown in pots. Choose pots at least 45cm (18in) in diameter and make sure there are plenty of drainage holes. Fill with a mixture of equal parts loam-based compost and loam-free compost.

Sowing: Sow successionally April to July
Even when temperatures are not below freezing, cold air can damage bean plants, so don't plant too early. Plant outdoors only after the last frosts.
Sowing seeds early indoors gives a faster and more reliable germination rate, particularly for runner beans. At the end of April sow a single bean seed, 4cm (1.5in) deep, in a 7.5cm (3in) pot filled with multipurpose compost. Water well, label and place on a sunny windowsill to germinate. Seedlings will be ready to plant out after about three weeks. Before planting, put in a cold frame to acclimatise.
Alternatively, beans can be sown directly in the soil between the second half of May and the middle of June. Plant two seeds next to your support about 5cm (2in) deep. Water well. After germination remove the smaller and less robust of the two young plants. As they grow, ensure the plants continue to twine around their canes.

Supporting plants:
Create a support before planting. Either make a wigwam with 2.4m (8ft) canes, lashed together with string at the top, or create a parallel row of canes, which have their tops tightly secured to a horizontal cane. Each row should be 60cm (23in) apart and canes spaced 15cm (6in) apart in the row.

Cultivation:
Having shallow roots regular and plentiful watering is vital. Runner beans should be watered particularly heavily, twice a week in dry weather, both when the flower buds appear and once they're open. Mulch when conditions are dry. Don’t hoe around bean plants too deeply or you may damage the roots. Beans capture nitrogen from the air, so make sure the soil contains the other essential ingredients, phosphorus and potassium. So for the fertiliser use something like 10-20-10. They leave the soil nitrogen-enriched even after harvest.

Pollination:
Runner beans are pollinated by honey bees and long-tongued bumblebees. Short-tongued bees do not pollinate the flowers because they cannot reach the nectar from the front and so nip a hole in the base to gain access. While there is no way to prevent this, sufficient bees usually visit the flowers in the conventional way for a good crop to set if other factors, such as water availability and temperatures, are favourable.

Harvesting: August to September. Matures in 75 days
Regular picking is essential - the more you pick, the more they produce. Most should bear pods from late July and cropping of all types can continue until the first frosts, or longer if plants are protected.
Runner beans are at their best when fresh, young and tender. For the best of their flavour and sweetness pick when they are 6 to 8 in (15 to 20cm) long.
They should be harvested when the pods are less than full length, snap easily and while the seeds are still small and pale in colour. As the pods get older they develop string and the pod-walls become more fibrous, with pronounced bumps on the surface indicating that the seeds are enlarging and that moisture is going into the seed from the pod.

Nomenclature:
Runner beans (Phaseolus coccineus) are also known as 'scarlet runners', a term that reflects the growth habit and red flowers of early introductions. Perennial, but not frost hardy, they are usually grown as a half-hardy annual.
White flowered cultivars are popular with commercial growers because, lacking the anthocyanin that is present in those with red flowers, they suffer less from bruising when transported.

Origin:
Members of the Fabaceae family, runner beans are native to the cooler, high-altitude regions (around 2000 metres) of central and northern South America, where they have been domesticated for more than 2000 years, although wild, small-podded plants are still found growing in the cool, partially shaded valleys of mixed pine-oak forests in Guatemala and Mexico.
Records show that the bean was introduced to Spain following Columbus’s second voyage to the New World in 1493 and then spread into the eastern Mediterranean. By the seventeenth century it was widely cultivated there and was also being grown in northern Europe as an ornamental, with John Tradescant (gardener to King Charles I) including a plant that has been identified as Phaseolus coccineus in a list of his plants in 1634.
The indigenous people of the region developed a system of companion planting runner beans with maize and squash known as “the three sisters” or “a guild of plants”: maize provides a natural pole for bean vines to climb; the beans fix nitrogen on their roots, improving soil fertility for the following year’s crop and also help to stabilise the maize plants, making them less vulnerable to wind damage; the shallow-rooted squashes act as a living mulch that suppresses weeds and reduces evaporation from the soil.
A short-day plant, it would not have initiated flowering if the nights were less than 10 hours long, so it is likely that it would not have flowered until late August or September and would have produced very few ripe seeds. Philip Miller, in The Gardeners Dictionary (1754), wrote that it was difficult to produce seed in England as “the fruit seldom comes to good”.

Development:
With time and selection the runner bean became daylength neutral, flowering early enough for pods to develop in Northern Europe and with this its use as a food crop increased. In the wet UK climate runner beans produced pods that were fleshier but still, like those in the wild, short and containing only three to five seeds.
For more than 100 years, and especially after the Second World War with an increased interest in exhibiting, breeding was aimed at producing longer pods. Today, with supermarkets looking for uniform, unblemished beans at around 25cm long, breeding programmes are selecting for flavour, better quality and for stringless beans, as well as for self-fertilising cultivars that give a better pod set and for novelties such as a short-podded, mangetout bean.
The runner bean has become a popular vegetable in Britain, but is also commonly used as an ornamental in other countries. In Germany, Scandinavia and in areas of the USA where high temperatures reduce setting but encourage flower production, gardeners grow them for their showy racemes of red, white and bi-coloured flowers, which attract bees, butterflies and in some parts of the USA, hummingbirds.