All of which is true, up to a point. Outside a tropical greenhouse, the banana will neither flower nor fruit in Britain. Come autumn, its leaves will die. And there is something slightly surreal about the idea of growing your own banana tree. Certainly, the first time you spot one waving from a sunlit corner of the garden, it calls for an instant reality check.
"But that's half the fun of growing them," says Mike Brisbane, a nurseryman who is raising a frost-resistant strain in deepest Herefordshire. "They're a fun plant, precisely because their physical presence is so unexpected." And they do have considerable presence. A mature banana plant in its late summer glory stands 15-20ft high; its heavily ribbed leaves can grow to 8ft or more.
Though I knew that banana plants could be grown indoors, I was astonished to learn that some species can be transplanted to the garden and left there throughout the winter. I was also surprised to learn that bananas have been flourishing in a handful of gardens around in Britain (admittedly most of them in Cornwall) for a century or more.
One of the hardiest species, Musa basjoo, was found in Japan and introduced into English gardens in the 1890s. Early collectors sought out examples of tropical plants growing at high altitudes, supposing these would be most tolerant of frost. Some root stock may even date from those pioneering days. Mike Brisbane acquired his first plant from the Royal Horticultural Society's collection at Wisley Gardens some 10 years ago, and this particular stock has been through the severest test of hardiness: "There was an unexpected cold spell, the temperature inside our polythene tunnel was minus 12C, and when I checked this banana plant it had lost all its top growth and the whole pot was frozen solid. So I reckoned it was dead and chucked it out. But next spring, up it came again."
From this hardy specimen thousands of plantlets are being grown using micro-propagation techniques, so effectively they are all clones. More recently a close relative of Musa basjoo which should prove even more resistant to frost turned up in a Belgian garden. It originally came from Sakhalin Island, off the east coast of Siberia, so Brisbane calls this his "Siberian banana". Its roots can survive ground frost and in its native habitat they can endure temperatures of minus 15C. But it is still early days for Musa basjoo (Sakhalin) in this country, and until a reasonable buffer stock is built up, Siberian bananas will not be for sale.
It is not always easy to judge from the young stems for sale in the nursery, their leaves still curled up, what the plant will look like in a few months' time. "It requires a certain degree of imagination," says Bris-bane. Since it is not always possible to manhandle a full-sized plant into a standard- sized car (the leaves tear easily), it is more practical to select smaller plants in, say, three-litre pots. These may be kept indoors until their growth demands they be moved out into conservatory or garden, the best season for planting out being midsummer so as to give enough time to put on growth before the leaves are cut back in autumn.
When planting out, adequate space must be allowed for future growth, so a plot of at least five square feet is needed. Bananas need generous feeding: they thrive on plenty of farm manure or other nitrogen-rich compost. They do not appreciate competition. And they like lots of water, so shallow, sandy soils are best avoided. A sheltered spot, out of the wind, is preferable, because the broad leaves tend to fray in a storm; and, besides, their strong forms look best against a brick wall or other architectural feature.
Indeed, Brisbane classifies the banana as an "architectural" plant: one grown for its good form rather than for flowers or fruit. He believes it should appeal to those who like palms, gunnera and other giant-leaved types. Certainly, the banana's big oval leaves with their thick, arching midribs and slightly raised veins have a strong tactile quality. They look especially refreshing just after it has rained, when droplets of water cling to their raised surfaces like so many pearls. No wonder that these same leaves, freshly washed, are used as plates for serving talis in south India or the components of that great Indonesian banquet, the rystafel.
Although it is the hardiest species readily available, Musa basjoo (or japonica, as it is sometimes called) is not the most handsome of the banana family. There are more exotic-looking red-leaved ones, and the numerous variants of Musa cavendishii, or Canary banana, have better form, though none could be expected to withstand a British winter.
Even the hardier Japanese or Siberian strains need some protection. Come autumn, the leaves should be sliced off near the stem (not so much a trunk as a leaf-sheaf). The top of the plant should be covered to prevent water dripping into the stem and freezing. Brisbane recommends wrapping the stem in some insulating material, a bubble polythene tent, straw, or even disused chimney pots to see it through the winter. And if the stem is damaged all is not lost: when stressed the banana tends to push up new shoots, provided the root system is not damaged.
While it is highly unlikely that a banana grown in a British garden would flower, those kept in a greenhouse might just bear a small hand of undersized fruits. If this happens the plant dies, so the stem must be cut right back to allow new offshoots from the root system to take its place.
The banana was one of the earliest fruiting plants to be cultivated by man: cave paintings in southern India dating from 500 BC show how it was cultivated then. Certain hardy strains have flourished for hundreds of years at high altitudes or in maritime climates as least as cold as our own.
But it is only recently that the banana has been raised as an ornamental plant rather than as a food crop. The vibrant green of their arching leaves provides a striking contrast with less exotic neighbours. But a good part of their allure comes down to the simple fact that they are not what one would expect to find in a British garden. They have the ability to shock, which is why, as Mike Brisbane puts it: "They are the ultimate anarchy plant."
! Musa basjoo plants may be ordered from Jungle Giants, Plough Farm, Wigmore, Herefordshire HR6 9UW (01568 770708). Visits by appointment only. Hardy Exotics 01736 740660; the Palm Centre 0181-876 3223.Reuse content