Kale originated in the eastern Mediterranean, most likely in the region around modern-day Greece and western Turkey. Its closest living wild relative is a plant called Brassica cretica, which still grows on rocky coastlines and cliffsides throughout the Aegean islands, mainland Greece, and Cyprus. From those ancient roots, kale spread across Europe and eventually the world, becoming one of the oldest cultivated forms of cabbage.
The Wild Ancestor in the Aegean
For decades, botanists debated whether cultivated cabbage-family crops descended from wild plants along the Atlantic coast of Europe or from species in the Mediterranean. A large-scale genetic study published in Molecular Biology and Evolution settled the question: the closest living relative of all cultivated Brassica oleracea, including kale, is Brassica cretica, a wild plant endemic to the eastern Mediterranean. The researchers found that B. cretica’s habitat extends from Greece through Cyprus and into parts of western Turkey, pointing to that region as the cradle of domestication.
Ancient writings support this. The Greek poet Nicander, writing around 2,100 to 2,050 years ago, described wild or semi-wild forms of B. cretica growing in Ionia, the western coast of present-day Turkey. This means people in the region were already familiar with the plant well before the common era, likely gathering it from the wild before anyone thought to cultivate it deliberately.
Ancient Greek and Roman Cultivation
By the fourth century BCE, both the Greeks and Romans were growing kale in recognizable forms. They cultivated curly-leafed and flat-leafed varieties, and the Romans called them “Sabellian kale.” These early cultivated types are considered the direct ancestors of the kale varieties grown today. Unlike heading cabbages, Brussels sprouts, or broccoli, which were bred later from the same wild ancestor, kale kept a loose, open leaf structure and never formed a tight head. That makes it one of the most ancient and least modified members of the cabbage family.
How Kale Got Its Name
The word “kale” traces back to Latin. The Roman word caulis, meaning “stem” or “stalk,” replaced the earlier Latin brassica as the everyday term for cabbage. Caulis moved into Germanic languages and Old English as cawel or col (the same root behind “coleslaw”). By around 1300 CE, the Scottish and northern English variant “kail” or “kale” had emerged to describe any leafy greens with curled or wrinkled leaves. The word survived mainly in Scotland for centuries before becoming the standard English term.
Kale’s Spread Across Europe
From the Mediterranean, kale moved north and west through Europe during the Middle Ages. Its ability to tolerate cold made it a staple crop in Scotland, Scandinavia, Germany, and the Low Countries, where longer winters limited the growing season for other vegetables. Scottish cuisine became so closely associated with kale that “kail” was slang for dinner itself, and a kitchen garden was called a “kailyard.”
In Italy, a distinct variety now known as Lacinato or Tuscan kale developed in the northern part of the country. Its long, dark, bumpy leaves (sometimes called dinosaur kale) set it apart from the curly types common in northern Europe. Meanwhile, Russian and Siberian kale varieties followed a different path entirely. Red Russian kale is actually a separate species, Brassica napus, rather than a variety of Brassica oleracea. It developed in Siberia and can survive temperatures down to minus 12°C (10°F) or below, making it exceptionally cold-hardy compared to its Mediterranean cousins.
Arrival in North America
Kale reached the Americas through multiple routes. Russian traders introduced Red Russian kale to Canada in 1885, where it picked up local names like “Canadian Broccoli” and “Ragged Jack.” In the United States, the plant explorer David Fairchild, who spent decades scouring the globe for useful crops on behalf of the U.S. Department of Agriculture, brought kale back from Austria-Hungary in the late 19th century. Fairchild is credited with popularizing dozens of foreign crops in America, and kale was among them.
For most of the 20th century, kale remained a niche crop in the U.S., grown mainly as animal fodder or as a decorative garnish. Its dramatic rise as a health food didn’t begin until the 2010s. Today, California, Texas, and Arizona are the primary commercial kale-producing states.
The Two Main Types Grown Today
Modern kale varieties fall into two broad categories. Scotch types have tightly curled, gray-green leaves and a sturdy texture that holds up well in soups and stews. Siberian types are blue-green with flatter, less crumpled leaves and a slightly milder flavor. Collard greens, which belong to the same botanical group (Brassica oleracea, Acephala Group), are close relatives that tolerate warm weather much better than kale does.
Nutritionally, kale stands out for its density of beta-carotene, vitamin K, vitamin C, and calcium. Genetic research into kale’s leaf development has found that genes involved in vitamin C production are regulated differently in kale compared to heading cabbages, which may partly explain why kale packs more of certain nutrients than its domesticated relatives. That nutritional punch isn’t a product of modern breeding. It’s a trait kale has carried since its days as a wild coastal plant on Mediterranean cliffs, soaking up sun and salt spray in thin, rocky soil.