By Larry Hodgson
Did you know that cabbage, kale and broccoli, as well as cauliflower, Brussels sprouts and even kohlrabi, all belong to the same species: Brassica oleracea? In other words, botanically, that they are all different forms of the same plant?
If such a proliferation of varieties for just one species surprises you, think that all breeds of dog, from the tiny Chihuahua to the gigantic Great Dane, and from the frail whippet to the musclebound mastiff, are all just dogs: Canis lupus familiaris. All of these variants of cabbage, whatever common names humans may have given them, trace back to just one wild plant: Brassica oleracea.
Wild cabbage, the ancestor of all cultivated cabbages, grows along the seashore in southern and western Europe. It’s often seen on steep slopes where other plants fail to thrive. It tolerates saline mists and alkaline soils well, especially the chalk cliffs on both sides of the English Channel.
Wild cabbage is a biennial: it lives only two years. In the first year, it forms a low rosette of large fleshy, tough, blue-green leaves. Their coloring comes from a white waxy coating—bloom—which covers them and protects them from both the blazing sun and salt damage.
In the second year, wild cabbage produces a flower stalk up to 2 m (7 ft) high and thousands of yellow flowers. After flowers die back, seed capsules are formed. They open in the fall, their seeds fall to the ground and then the plant dies.
A new generation is then born from the seeds the following spring.
The First Cultivated Cabbages
The initial domestication of wild cabbage is lost in the mists of time. It is also quite possible that cabbage was domesticated several times in different regions of Europe, starting around 1000 years BCE. Certainly, it was known to the ancestors of the Greeks and Romans.
Kale was the first cabbage to be developed by humans, around the 5th century BCE. Indeed, with farmers re-sowing the seeds of the best-tasting and easiest-to-grow plants every year, wild cabbage gradually turned into domesticated kale. Along with larger, thinner leaves and a less bitter taste than wild cabbage, kale offers an erect stem, which makes harvesting easier. Leaves are harvested as needed through the summer, starting from the base.
Often kales have curly leaves. These are highly condensed, allowing you to grow more “edible material” in less space.
One very old dark-leaved strain of kale, originally called black kale, Tuscan cabbage or Lacinato kale, has been renamed dinosaur kale by foodies, because its bumpy leaves are said to resemble dinosaur skin. You might want to use that term when you introduce the strong-flavored vegetable to your kids! It was developed in Tuscany in the 18th century.
Head cabbage was gradually selected from kale. Indeed, selecting plants with a tighter terminal bud which therefore occupied less garden space eventually led to a very dense, round head we know as head cabbage or headed cabbage today.
Head cabbage became popular in Rome around the 1st century CE and the Romans helped spread it throughout their empire. Today, there are a vast number of varieties of headed cabbage, from red cabbage to savoy cabbage (with wrinkled leaves) and with round or pointed heads. They even have different uses (early cabbage for fresh eating; winter cabbage for storage, etc.).
The stem of a cabbage is also edible and so kohlrabi was gradually developed from plants with a stem more swollen and less fibrous than normal, which resulted in more to eat. The very rotund kohlrabi we know today was already being grown in Germany in the 1st century EC.
Cabbage flower buds are also edible … but since the plant is a biennial, you normally have to wait until the second year to harvest them. So, ancient farmers began to choose cabbage that matured at a younger and younger age, and this eventually led to annual cabbages. They’re capable of completing their growth cycle, from seed to bloom, in a single summer.
Of this group of cabbages, some were then cultivated for their flower buds. Cabbages with dense flower stalks first appeared between the 2nd and 6th centuries, but it wasn’t until the 15th century that cauliflower as we know it came to fruition. We harvest it for eating at the beginning of flowering, hence its still white color.
Broccoli appeared in Italy around the 16th century, derived from annual cabbages that were harvested when the flower buds were more advanced than those of cauliflower, so fully green, but before they bloomed.
The last cabbage to really become a popular vegetable around the world (because there are still a lot of ancient varieties, such as marrow cabbage, perpetual kale, collard greens and Chinese broccoli, which are less well known in our gardens) is Brussels sprouts, which came, of course, from Belgium and was developed around the 16th century, although precursors are known from at least the 5th century EC. This plant produces the tall stems and large leaves of kale, but rounded cabbage-like buds emerge from the leaf axils.
The Oddest Cabbage
Perhaps the most bizarre cabbage of all is Jersey cabbage, a very large form of kale. In a climate where the winters are very cool but frost free, such as in the Channel Islands, it reaches a great height, sometimes up to 5 m (16 ft). The lower leaves are harvested to feed livestock as the plant grows, leaving a tall “trunk” with a cluster of leaves at the top. The plant almost looks like a palm tree! When Jersey cabbage blooms, the stems are cut and dried to make walking sticks. Under less ideal conditions, notably a less than 12-month growing season, Jersey cabbage will simply look like an extra-tall kale.
Some non-heading cabbages are grown as ornamental plants. You’ll seed them sold as ornamental cabbage or ornamental kale, even flowering cabbage, although their colorful rosettes are not flowers, but made up of leaves. Under the influence of cool autumn days, the leaves change color to pink, red, white or multicolored. Gardeners grow them in flowerbeds and as fall decorations for containers, etc. Despite their unusual coloring, these cabbages are still perfectly edible, and upscale restaurants use their surprisingly colored leaves as a food garnish.
More to Come?
Of course, the evolution of edible cabbages isn’t over. There is so much more to discover! Think Romanesco broccoli, kalettes and gai lan (Chinese kale), not to mention the new cauliflower colors like orange, green and purple, etc. Such plants have arrived timidly in our gardens and our plates and might yet become staples.
What will cabbages look like in another two hundred years? I don’t know, but I bet that we will then be growing cabbage on the moon and who knows what kind of shape moon cabbage it will take on!