Brassica oleracea in its leafy, non-heading forms (var. acephala and var. sabellica, curly kale; var. palmifolia, the Tuscan cavolo nero; var. viridis, collard greens; var. alboglabra, Chinese kale or kai-lan); together with the separate species Brassica napus (Russian and Siberian kale) and Brassica carinata (Ethiopian kale)
Origin: The Mediterranean and Atlantic coasts of Europe, where wild cabbage (<em>Brassica oleracea</em>) was first cultivated as leafy kale in the ancient Greek and Roman world; with a wholly separate domestication of Ethiopian kale (<em>Brassica carinata</em>) in the highlands of the Horn of Africa
Kale is the oldest of the cabbages and the closest of all the cultivated Brassica oleracea to its wild ancestor. The wild cabbage is a sprawling, bitter, blue-grey perennial of the sea cliffs and limestone headlands of the Mediterranean and the Atlantic coasts of Europe, and from this single unpromising plant human selection drew out the most astonishing range of vegetables of any species on earth: the cabbage by swelling the terminal bud into a head, broccoli and cauliflower by arresting the flower, kohlrabi by swelling the stem, the Brussels sprout by multiplying the side buds. Kale is what the wild cabbage becomes when none of these things is done to it. It is, quite simply, a leaf cabbage that never learned to form a head, and the Latin name of its principal group, var. acephala, says exactly that: 'without a head'.
Because it is the least altered, kale is almost certainly the most ancient cultivated form, the leafy cole that the Greeks called krambe and the Romans brassica, grown and eaten for centuries before the heading cabbages of the medieval north existed. From that loose-leafed ancestor the cultivators of Europe drew their kales: the frilled and ruffled curly kale (var. sabellica) of the cold north; the long, dark, blistered leaves of the Tuscan cavolo nero (var. palmifolia); and the broad, flat, smooth-leafed collard (var. viridis). At the eastern edge of the plant's range the Chinese selected their own leafy and flowering cole, the kai-lan (var. alboglabra), the Chinese kale.
Kale is also one of the rare vegetable names that gathers three different species under a single word. Besides the many kales of Brassica oleracea, the cold-hardy Russian and Siberian kales belong to Brassica napus, the swede and oilseed-rape lineage, and the gomen of the Ethiopian table is Brassica carinata, the Abyssinian mustard, domesticated in the Horn of Africa entirely apart from the European cole. Three species, one humble idea: the green leaf of a cabbage that was never made to close.
Kale travelled as the hardy green of the poor, the plant that fed northern Europe through the winters when little else would grow, and only in our own age became the darling of the health-food shelf.
From the leafy cole of the Greek and Roman Mediterranean, kale spread north with the legions and the monasteries into a belt of cold-winter countries that would make it a true staple. It became the kale of Scotland, where the word itself is Scots and the kitchen garden was the kaleyard; the colcannon of Ireland; the boerenkool of the Low Countries; the Grünkohl of north Germany, eaten after the first frost had sweetened it; and the grønlangkål of the Danish Christmas. In the wet green northwest of Iberia it became the couve of the Portuguese caldo verde and the berza of the Galician caldo gallego. Carried east along the Silk Road, Brassica oleracea reached Tang China and was selected there into the kai-lan. And carried by Europeans across the Atlantic, the broad-leafed collard took root in the American South, where the enslaved cooks of West African descent made it, simmered long with smoked pork and its pot likker, one of the defining dishes of the region; the same couve went south with the Portuguese to Brazil, finely shredded into the couve à mineira that sits beside every feijoada.
Two further streams complete the picture. With British colonisation, Brassica oleracea kale and collards reached the highlands of East Africa and became the dominant sukuma wiki, the everyday green of Kenya and Tanzania, where they met the older Ethiopian kale, Brassica carinata, which had itself long since spread south down the highlands from the Horn; for the Ethiopian highlands had domesticated that native kale, the gomen of the Ethiopian table, entirely apart from the European cole. And in the late twentieth century the Tuscan cavolo nero, the curly kale, and the Russian kale (Brassica napus) all converged in California, where a Mediterranean peasant green was reinvented as the emblem of the modern superfood, massaged raw into salads, baked into crisps, and blended into the smoothie.
Kale occupies two quite different places in the world's kitchens at once. Across much of Africa it is a daily staple of the first importance: sukuma wiki, the braised collard-kale of onion and tomato, is eaten with the maize porridge ugali by tens of millions in Kenya and Tanzania, and the spiced gomen of Brassica carinata is fundamental to the Ethiopian and Eritrean table. Across the cold north of Europe it remains the traditional winter green of national comfort dishes: the Dutch boerenkool stamppot, the German Grünkohl mit Pinkel, the Danish grønlangkål, the Irish colcannon, the Portuguese caldo verde, and the Galician caldo gallego. In southern China the kai-lan, dressed with oyster sauce, is one of the most-ordered greens of the Cantonese table and the dim sum trolley. And in Brazil the finely shredded couve à mineira is the inseparable companion of feijoada.
Then, from around 2010, kale underwent one of the most sudden reinventions in the history of any vegetable. Long dismissed in the English-speaking world as cattle fodder or a garnish for buffet tables, it was taken up by the Californian and wider Western health-food movement as the archetypal 'superfood', prized for its density of vitamins and antioxidants. The Tuscan cavolo nero, rebranded as 'dinosaur' or 'lacinato' kale, and the tender Red Russian kale became fashionable restaurant greens; the massaged kale salad, the kale chip, and the kale smoothie became ubiquitous. A peasant survival crop of the European winter and the African dry season had become, within a few years, a global symbol of wellness, and one of the few vegetables ever to be celebrated with its own annual day.
Historical Journey of Kale
Ethiopian Highlands, Horn of Africa — c. 2000 BCE
In the cool, high plateaux of the Ethiopian Highlands, far from the Mediterranean cradle of the European cole, the farmers of the Horn of Africa domesticated a kale entirely their own. Ethiopian kale, Brassica carinata, also called Abyssinian mustard, arose in antiquity as a natural cross between the black mustard and a wild cabbage relative, and was taken into cultivation in the highlands for both its oil-rich seed and its tender leaves. It is no relation, in the immediate sense, to the European kales of Brassica oleracea; it is a separate species, a separate domestication, and a separate culinary tradition, and it makes the Horn of Africa one of the genuine independent cradles of the leaf cabbage. The leaves, robust and slightly mustardy, are the gomen of the Ethiopian and Eritrean table: stripped from their stems, chopped, and stewed long with onion, garlic, ginger, and the spiced clarified butter niter kibbeh into a soft, savoury mound of greens that is one of the constants of the national cuisine, eaten with the great sourdough flatbread injera both on its own and beside the meat and lentil stews of the feast. From this highland cradle Brassica carinata spread north into Eritrea, where the same gomen anchors the table, and south down the long spine of the East African highlands as a hardy leaf vegetable and oilseed, reaching the Kenyan and Tanzanian highlands over a long earlier age, well before any European cole. There the ancient African kale never became the single great staple it was in Ethiopia, but it endured as one of the everyday highland greens, and it would in time stand beside the collard that British settlers introduced, the two blurring together in the modern Kenyan greens dish, sukuma wiki. Where Europe and Asia drew their kale from a single Mediterranean ancestor, Ethiopia grew its own, and sent it south to meet the European cole in the highlands of Kenya.
Ancient Greece and the Mediterranean Coast — c. 600 BCE
The wild cabbage, Brassica oleracea, grows to this day on the sea cliffs and limestone headlands of the Mediterranean and the Atlantic coasts of Europe, a sprawling, bitter, blue-leafed perennial that is the single ancestor of kale, cabbage, broccoli, cauliflower, kohlrabi, and the Brussels sprout alike. The first of these to be cultivated was the simplest: the leafy, non-heading cole that the Greeks called krambe, grown for its loose, dark, slightly bitter leaves long before any cabbage had learned to fold itself into a head. The Greeks held the cole in high regard as both food and medicine; the physician Hippocrates of Kos prescribed it, and later the Romans would call it the brassica and consider it a cure for almost everything. This ancient leafy cole, eaten boiled or dressed raw with oil and vinegar, is in all but name the kale we know, and the Greek table still keeps the habit in the lahanosalata, the winter salad of dark, loose-leafed cabbage dressed simply with olive oil and lemon. From this Mediterranean hearth the leafy cole would travel north and east to become, in a hundred local forms, the kale of half the world.
Rome and the Italian Peninsula — c. 50 CE
Rome inherited the Greek cole and made it the most esteemed vegetable of the Republic. Cato the Elder devoted pages of his farming manual to the brassica, declaring it surpassed all other vegetables and prescribing it, raw and cooked, as a remedy for every complaint of the body; Pliny catalogued its many sorts. The Romans grew leafy, loose-headed coles of the kale type, boiled long and dressed with oil, cumin, and vinegar, and carried the plant the length of their empire, planting it in the cold provinces of the north where it would in time become the winter staple of whole nations. In Italy itself the leafy cole never gave way entirely to the heading cabbage, and it survives in its noblest form as the cavolo nero, the 'black cabbage' of Tuscany, with its long, narrow, almost black, blistered leaves. Cavolo nero is the soul of the great Tuscan peasant soups, above all the ribollita, the 'reboiled' soup of cannellini beans, bread, and dark kale that is simmered, cooled, and simmered again until it is thick enough to stand a spoon in, the very emblem of the cucina povera.
Tang Dynasty China, Guangdong — c. 600 CE
Carried east along the Silk Road, the Mediterranean cole reached China by the Tang dynasty, and there the cultivators of the south selected it into a kale unlike any in the West: the kai-lan, or Chinese kale, Brassica oleracea var. alboglabra. Chinese farmers favoured thick, sweet, juicy stems, smooth blue-green leaves, and small white flowers, a plant grown as much for its tender stalk as for its leaf and quite distinct from both the leafy kales of Europe and the dense-headed broccoli of Italy that shares its ancestry. Kai-lan became, and remains, one of the most beloved leaf vegetables of southern China and the Cantonese kitchen, a fixture of the home table, the restaurant, and the dim sum trolley. Its classic and almost invariable preparation is the simplest: the whole stems are blanched briefly in oiled, salted water to set their vivid green, drained, laid on a plate, and dressed with a glossy spoonful of oyster sauce and a drizzle of hot oil and sesame, a dish whose clean, faintly bitter sweetness and crisp stem have made it the standard green of Cantonese cooking across the entire Chinese diaspora.
Galicia, North-West Spain — c. 1480 CE
In the cool, wet, green northwest of the Iberian Peninsula, the leafy cole became the everyday vegetable of the Galician table, where it is called berza. Galicia, a land of small farms, Atlantic rain, and a cuisine built on pork, potatoes, and greens, made the kale the heart of its great communal pot, the caldo gallego: a slow-simmered broth of white beans, potato, and a generous quantity of berza or grelos, enriched with cuts of cured pork, salt-cured pork bones, and the fatty unto that gives the broth its character. Eaten the length of Galicia as the warming meal of the long wet winters and at every village festa, caldo gallego belongs to the same broad Atlantic family of bean, potato, and kale soups that runs along the whole northwestern seaboard of Iberia, sibling to the caldo verde just across the Portuguese border. The kale here is no garnish but a defining element, simmered until meltingly tender and lending the broth its deep green and faintly bitter backbone. From this Galician hearth the leafy cole spread west into the neighbouring Minho of Portugal, where it would take its most famous Iberian form.
Scotland and the British Isles — c. 1500 CE
Nowhere did kale sink deeper into the language and the life of a people than in Scotland. The cold-hardy curly kale thrived where finer vegetables failed, standing green through the frosts of the Scottish winter, and it became so completely the staple green of the cottage garden that the kitchen plot itself was named for it: the kaleyard. The word 'kale' came to mean dinner in general, so that to be asked to 'take your kale' was simply to be invited to a meal, and a whole school of sentimental rural fiction was later christened the 'kailyard'. The Scots ate their kale above all in broths: kale brose, in which the green is cooked into a beef or ham broth thickened with toasted oatmeal, and the older kale-and-barley broths of the whole Celtic Atlantic west, the direct ancestors of the medieval pottage. The same loose-leafed cole had fed the British Isles since Roman times, simmered into the daily pottage of the medieval poor with oats, onions, and herbs. Older still, the wild cabbage itself, the bitter sea-cliff ancestor of every cole, clings to this day to the Atlantic shores of Cornwall, southern Ireland, and Brittany, and the gathering of its leaves into a simple shoreline broth reaches back to the very dawn of European vegetable cookery, long before the plant was ever sown. Hardy, cheap, and ever-present, kale was the green that carried Scotland and its neighbours through the winter, long before the potato arrived to share the task.
Minho, Northern Portugal — c. 1520 CE
In the Minho, the wet, green province of northwestern Portugal, the leafy cole took the form of the couve galega, a tall, dark, loose-leafed Galician kale grown on a long bare stalk, and from it the Portuguese made what many call their national soup: caldo verde, 'green broth'. The couve is sliced as fine as a thread, almost a chiffonade, and stirred at the last moment into a silky purée of potato and onion enriched with good olive oil and rounds of smoky chouriço, then cooked for only a few minutes so that it keeps its vivid green and faint bite. Served with a thick slice of broa, the dense Portuguese corn bread, torn and dipped, caldo verde is eaten at every kind of occasion across the country, from the weeknight supper to the wedding feast and the great summer street festival of São João in Porto. The dish rests entirely on the fineness of the kale's cut and the quality of the oil poured over at the table, and it has carried the couve, and the taste of the Minho, across the whole Portuguese-speaking world.
The Netherlands — c. 1550 CE
In the Low Countries the curly kale, the boerenkool or 'peasant's cabbage', became the great vegetable of the Dutch winter, and it gave the English language the word borecole into the bargain. The Dutch eat it above all as boerenkool stamppot, one of the family of sturdy winter mashes in which potatoes boiled soft are crushed together with a cooked vegetable, finished with butter, milk, and a generous grating of nutmeg, the spice the Dutch grate over everything, and crowned with a length of smoked sausage, the rookworst. Boerenkool stamppot is the archetype of Dutch comfort food, plain, filling, and warming, the dish of the cold dark months and the first hard frosts of the year. For the kale, like all its kind, is sweetest after a frost, the cold turning its starches to sugar, and the Dutch hold that boerenkool should not be picked until the first frost has touched it. From the Netherlands the curly kale spread east into the neighbouring lands of northern Germany, where it would acquire a whole winter culture of its own.
Oldenburg and North Germany — c. 1600 CE
Across the flat, cold north of Germany, from Oldenburg and Bremen to the Frisian coast, Grünkohl, the curly kale, became the centre of one of the most exuberant winter food traditions in Europe. Here too the rule is that the kale must not be cut until the first frost has sweetened it, and the long winter is marked by the Kohlfahrt or Grünkohlfahrt, the communal 'kale walk': parties tramp through the frozen countryside hauling a cart of schnapps, play games along the way, and end at an inn for an enormous feast of Grünkohl mit Pinkel. This is the dish of the season: curly kale stewed long and dark with stock, lard, and mustard until soft and savoury, served with boiled potatoes and a battery of pork, above all the Pinkel, a fatty, smoky, oat-and-onion sausage peculiar to the region, alongside Kassler smoked chop and cooked sausage. The feast culminates in the crowning of a Grünkohlkönig, a 'kale king', who must host the following year's walk. Hearty, fatty, and warming against the northern cold, Grünkohl mit Pinkel is to the German winter what the barbecue is to the American summer, a whole social season built around a single green.
Minas Gerais, Brazil — c. 1620 CE
Portuguese colonists carried the couve across the Atlantic to Brazil, where the broad, flat-leafed collard kale found a warm second home and became one of the most characteristic greens of the Brazilian table. In the state of Minas Gerais above all it is prepared as couve à mineira, 'kale in the manner of Minas': the leaves are stripped from their stems, stacked, rolled tight, and sliced into the finest possible ribbons, then thrown into a very hot pan with garlic and a little oil or bacon fat and tossed for only a minute or two, so that they stay bright green, glossy, and just wilted, retaining a fresh, faintly bitter bite. Quick, simple, and vividly green, couve à mineira is the inseparable companion of feijoada, the great black-bean and pork stew that is Brazil's national dish, where its clean freshness cuts the richness of the beans and meat; it sits equally beside the everyday plate of rice, beans, and grilled meat. The Portuguese couve, transplanted to the tropics, became in Brazil a daily green eaten by the whole nation.
Denmark and Scandinavia — c. 1650 CE
In Denmark and across Scandinavia the curly kale, grønkål, became the green of the deep midwinter and, above all, of Christmas. The Danish Christmas table would be incomplete without grønlangkål, 'long kale': curly kale boiled until tender, finely chopped, and folded into a rich creamy sauce of butter, flour, and milk or stock, seasoned with sugar, salt, and pepper into a thick, soft, comforting purée of greens. It is served hot beside the salted and smoked pork of the season, the hamburgerryg and the boiled ham, and at the Christmas feast itself, the cream and the sweetness tempering the slight bitterness of the frost-touched kale. Like its German and Dutch cousins, the Danish kale is held to be at its best only after the first hard frost has sweetened it, and grønlangkål belongs to the darkest, coldest weeks of the year, a dish of warmth and richness against the long northern night. Cold-hardy beyond almost any other vegetable, kale stood green in the Scandinavian garden when all else had failed, and earned its place at the heart of the midwinter feast.
The American South — c. 1660 CE
European settlers carried the broad-leafed collard, a flat-leaved loose kale, to the American South, but it was the enslaved cooks of West African descent who made it one of the defining dishes of the region. Drawing on a deep West African tradition of slow-cooked leafy greens, they took the hardy collard, which grew readily in the southern heat and stood through the mild winters, and simmered it long and slow with smoked and cured pork, a ham hock or pork belly, until the leaves were meltingly soft and the cooking liquor had become the prized 'pot likker', a deeply savoury broth sopped up with cornbread and valued as much as the greens themselves. Seasoned with onion, a little vinegar or hot pepper sauce, and the smoke of the pork, collard greens became, with cornbread and black-eyed peas, the heart of soul food and of the Southern table, eaten at the everyday supper and, by tradition, at the New Year, when a mess of greens is said to bring a year of money. Kale and collards, near-identical loose-leafed coles, are used almost interchangeably, and the dish stands as one of the great contributions of the African American kitchen.
Ireland — c. 1700 CE
In Ireland the curly kale, cál, was the winter green of the cottage garden long before the potato arrived, and when the two met they produced one of the most loved dishes of the Celtic world: colcannon. The name comes from the Irish cál ceannann, 'white-headed cabbage', and the dish is a buttery mash of floury potatoes folded through with kale or cabbage softened in butter, brightened with spring onion, and served with a well of melted butter in its centre. Kale is the older and more traditional green of the two, giving a more rustic and intensely flavoured colcannon than the milder cabbage of the modern version. Colcannon was bound up with the rituals of the Irish year, above all Samhain, the feast that became Halloween, when charms were hidden in the mash to tell the eater's fortune: a ring foretold marriage within the year, a coin wealth, a thimble a life unwed. Sung of in folk song and eaten at every cottage hearth, colcannon made kale, with the potato, the comfort food of Ireland, the marriage of the ancient leafy cole and the new American root.
Kenya and the East African Highlands — c. 1900 CE
The cool, fertile highlands of East Africa came to their kale by two roads. Down the long spine of the highlands from the Ethiopian north, over a great span of time, had already spread the indigenous African kale, Brassica carinata, grown as a hardy highland green; and to it British settlers, during the colonial period, added the European collard and curly kale of Brassica oleracea, which took root so thoroughly that it became, within a few generations, the dominant everyday green of the whole region. Today the two are largely blurred together under a single Swahili name: sukuma wiki, meaning 'to push' or 'stretch the week', for this is the cheap, abundant, ever-available green that stretches a household's food from one payday to the next. The leaves, whether the European collard, true curly kale, or the older African carinata, are stripped, shredded, and braised quickly with onion, tomato, and a little oil into a soft, savoury relish of greens, sometimes sharpened with chilli or a squeeze of lemon. Sukuma wiki is eaten across East Africa at almost every meal, above all as the partner of ugali, the stiff maize porridge that is the regional staple: a scoop of ugali pressed into the greens and their juices is, for tens of millions of people, the daily meal. Two kales, one African and ancient, one European and colonial, had met to become the most important everyday vegetable of the continent.
California, United States — c. 1990 CE
In California, at the end of the twentieth century, the humble kale of the European peasant winter was reinvented as the emblem of the modern health movement. The cooks of the Californian food revolution, steeped in the Mediterranean kitchen, took up the Tuscan cavolo nero, which they rechristened 'dinosaur' or 'lacinato' kale, and grew it alongside the frilled curly kale and the tender, sweet, purple-veined Red Russian kale, the last a cold-hardy variety of the separate species Brassica napus that Russian traders had carried across the Pacific to the American west. From around 2010 kale became the defining 'superfood' of the age, celebrated for its density of vitamins and antioxidants and suddenly inescapable: massaged raw with oil, salt, and lemon until tender enough to eat as a salad; baked into the crisp, salty kale chip; and blended into the green smoothie. A vegetable long dismissed in America as cattle fodder or a decorative garnish for salad bars became, within a few short years, a global symbol of wellness, complete with its own National Kale Day, in one of the most complete reversals of fortune in the history of any vegetable.
