Most runners beans need pollination from another plant to produce beans. They need bees to carry the pollen from flower to flower and they also need moisture at the roots. But with fewer bees and drier summers, crops have been unpredictable.
Lack of pollinating bees in some areas may be contributing to poor bean set, so anyone suffering will do well to consider choosing the recently developed self-fertile varieties.
'Moonlight' was the first to be developed, a white flowered variety that is self-fertile. This meant it no longer needed bees to transfer pollen from other nearby beans in order to set a good crop. This is now joined by 'Firestorm', the first self-fertile scarlet-flowered runner bean.
Runner Bean 'Firestorm' is easy to grow and produces masses of scarlet-red flowers, which set well even in poor weather or high temperatures. It produces prolific, smooth pods that are up to 30cm long.
The beans are stringless and when picked young they have all the beauty of a classic runner with a more succulent texture closer to a French bean.
It's also worth ensuring beans never go short of moisture at the roots. By the time flowers start to develop, the plants will have twined their way to the top of supports, and their lush foliage acts as an umbrella, keeping rainfall away from the soil beneath wigwams. Give the soil round beans a good drench at least once or twice a week to help new flowers set, and a good crop of tender, stringless beans develop.
Also, make sure you don't miss any beans, as these pods will grow old and set seed. Allowing this to happen can trigger a response in plants to stop producing further flowers. Be vigilant, harvesting regularly, and picking off and discarding old beans rather than leaving them on the plant. With a little care and attention runner beans can continue cropping until the end of September.
- Awarded the RHS Award of Garden Merit
In 2013 Runner Bean 'Firestorm' was awarded the Royal Horticultural Society Award of Garden Merit (AGM).
A key indicator that this variety is worth growing in your garden.
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.
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.
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.
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: 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.
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.
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”.
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.
- Awarded the RHS Award of Garden Merit
- Additional Information
Packet Size 50 grams Average Seed Count 45 seeds Common Name Runner Bean Family Leguminosae Genus Phaseolus Species coccineus Cultivar Firestorm Hardiness Hardy Annual Natural Flower Time July to August Height 3m (10ft) Spread 30cm (12ft) Time to Sow Sow successionally April to July Harvest Most should bear pods from late July Time to Harvest Matures in 75 days