Coleworts
Wild colewort (Brassica oleacera) is native to the coast of western and southern Europe. It was first domesticated in around 1,000 BCE and was consumed as a leafy vegetable during Antiquity. Over time, it became a widespread staple throughout Europe, from where its cultivation spread to the rest of the world.
We know colewort today as a number of widely eaten vegetables such as kale, cabbage, broccoli, or kohlrabi. Brassica oleacera was bred into many distinct forms over the course of history; what seem to be different plants are actually a single species, bred selectively to favor different traits. For each variety, a different part of the plant was emphasized and enlarged to provide a crop.
Trait selections
Seasons
Colewort is a biennial plant that is native to mild, coastal climates. Biennial plants follow a two-year life cycle. The first year is dedicated to vegetative growth, which slows down when winter arrives and the plant goes dormant. The second year, the plant emerges from dormancy and grows a flower spike. After flowering and producing seeds, the plant dies.
The stage of flowering and producing seed is referred to as “bolting”. Because colewort is a cool-weather plant, warm soil temperatures can trigger bolting early, during the first year. Basically, the plant tries to set seed before it could potentially die from drought or hot weather. Bolting is undesirable because the plant diverts all of its energy to flowering, and the flavor and quality of the rest of the plant declines or never develops.
Many cole varieties are grown not as biennials, which would normally overwinter, but as annuals. These varieties are selected to quickly grow and be harvested before they bolt or go dormant.
Because we grow coles as both annuals and biennials, they can be grown either as summer, fall, or winter crops, depending on how their growth cycle is manipulated. In the Pacific Northwest, we have three options:
Summer harvest: plant a fast-maturing variety in spring and harvest it in early summer, before it bolts.
Fall harvest: plant in late summer and harvest in fall.
Winter harvest: plant in late summer and harvest in winter or early spring, when it starts growing again.
Coles are adaptable, but a more maritime climate, like along the coast, is ideal since they have fewer extreme temperatures to deal with than further inland.
Naming conventions
“Cabbage”, “crucifer”, or “brassica”? The language used when talking about Brassica oleacera is easily confusing. All three of these terms are used in a broad sense to refer to many different plants, but each actually has a specific meaning.
“Brassicas” refers to plants in the genus Brassica, which includes several related species, including turnips, mustards, and rutabagas. “Brassica” was a Latin name for coles.
“Crucifer” comes from “Cruciferae”, the old name for the Brassicaceae family. Meaning “cross-bearing”, the name was chosen for the four petal, cross-shaped arrangement found on cole flowers.
“Cabbage” is often used similarly to “Brassicas”, but in fact refers specifically to head-forming coles.
I’ve opted to use the older term “colewort” to refer to Brassica oleacera because, linguistically and historically, it’s the only one that refers to the actual plant. Its cultivated varieties are “cole crops” or simply “coles”.
The common names of cultivated cole varieties are a bit all over the place, but their names do actually betray their origins as the same plant. “Cole”, “kale”, “collards”, “broccoli”, “cauliflower”, and “kohlrabi” are all ultimately derived from the Latin word “caulis”. “Cabbage” is the odd one out; its name comes from the Latin “caput”, meaning “head”. Older sources referred to it as “cabbage colewort”.
Compare this with French, where every vegetable included in this article is named a variation of “chou” (the French word for “cole”): “chou-fleur”, “chou pommé”, “choux de Bruxelles”, “chou-rave”, etc.
Species and varieties
Coleworts
Colewort (Brassica oleacera)
Leaf selections
Kale
Collards
‘Cavolo nero’
‘Spigiarello’
Tree collards
Terminal bud selections
Cabbage
Savoy cabbage
Auxiliary bud selections
Brussels sprouts
Kale sprouts
Flowering stem selections
Broccoli
Sprouting broccoli
Gai lan
Broccolini
Meristem selections
Cauliflower
‘Romanesco’
Sprouting cauliflower
Stem selections
Kohlrabhi
Leaf selections
The earliest forms of cultivated colewort were varieties selected for large leaves. These leaf selections were commonly eaten in Antiquity. Today, they are commonly called kale or collards. Originially, there was no distinction made between kale and collards. Today, the distinction has more to do with geographic provenance than anything else, with kale mostly coming from colder climates, and collards from the southeast of the US.
These leafy cole crops are hardy plants that overwinter successfully in our climate. They’re best-suited to a fall and winter harvest, but can be grown for an early summer harvest as long as they don’t bolt.
Kale and collards include green and purple (“red”) varieties.
Kale is simply the Scottish variant of the word “cole”. Kale varieties are leafy coles generally from colder climates. There are curly, green, and red (purple) varieties of kale.
Collards are a leaf selection that generally has wider, flatter leaves than kales. Collards are often considered to be more heat-resistant and better suited to summer cultivation than “kales”. Collards are typical of the southeastern US. They were a popular food in Africa, where they were likely introduced by the Portuguese. Collards were in turn brought to the United States by African slaves as early as the late 1700s. The name “collards” is a Southern American modification of the word “colewort”. Portuguese varieties are known as “couve”.
‘Cavolo nero’ is Italian for “black cole”. This variety is sold variously as “Tuscan kale”, “black kale”, or “lacinato kale”. “Lacinato” is a marketing name that just means “curly”. This variety is popular in northern Italy and now common in our region.
‘Spigiarello’ is a variety originally from southern Italy, often these mislabeled a type of broccoli, but they’re grown entirely for their leaves. The leaves are long, wavy and thin.
Tree collards are a perennial form of collards. They are not as cold-tolerant as annual/biennial collards, generally being considered cold-hardy down to 20°F at best, and are recommended for warmer or milder parts of the Pacific Northwest, such as Northern California or the coast. Interest in breeding tree collard varieties may yield more cold-resistant varieties in the future.
Ethiopian collards and Siberian kale
Ethiopian collards, or “texsel greens” are similar to kales and collards but are actually a different species, Brassica carinata, that came about from crossing cabbage (Brassica oleacera) with black mustard (Brassica nigra). Ethiopian collards are more heat-resistant than kale and collards and seem like a good candidate for a summer crop. I can’t find any confirmation, but I would expect that they don’t overwinter as well in the Pacific Northwest.
Like Ethiopian collards, Siberian kale, a leafy green that looks similar to kale, is not the same species as kale. Siberian kales are leafy varieties of rutabagas (Brassica napus), a cold-hardy relative.
Terminal bud selections
Developed during the Middle Ages in northwestern Europe, cabbages have tightly bundled leaves that form a large head.
The cabbage head is basically a massive leaf bud; cabbages were bred to enlarge the plant’s terminal bud, which is located on the tip of the main stem.
The large leaves that grow below the cabbage head, which look very similar to collards or kale, can be eaten. So can the flowering shoots that grow when the plant bolts.
There are green, red (purple), and Savoy varieties of cabbage. Savoy cabbage varieties have crinkly leaves.
Cabbages come in summer and winter varieties. Summer varieties are selected to grow quickly and resist bolting. They have looser, more tender leaves and don’t store as well. They can be harvested as long as they don’t bolt, which becomes increasingly difficult to prevent as summer progresses.
Winter varieties are grown starting in late summer for a late fall or winter harvest. In colder climates, they can be harvested in late fall and placed in storage. These hardy varieties take longer to mature and have tight heads that prevent spoilage.
Auxiliary bud selections
Brussels sprouts are similar to cabbage in that they are enlarged buds. In this case, however, they grow from axillary buds, which would normally grow into side shoots. Essentially mini-cabbages, they’re similar in all ways but size.
The leaves that grow in between the sprouts are edible too, and often removed from the plant during its cultivation. When ready to harvest in fall and winter, after the first frosts, the whole stalk is cut. Brussels sprouts are very cold-hardy and can easily overwinter in our climate. Like other coles, they also come in purple varieties.
Kale sprouts are also known as “kalette” or “lollipop kale” and are the product of a cross between Brussels sprouts and kale. The heads don’t grow as tightly as Brussels sprouts.
Flowering stem selections
Broccoli are varieties that were selected for their flower stems and flower buds. The word “broccoli” comes from Italian, meaning “cole shoots”.
The most common variety of broccoli (called “Calabrese broccoli” in the UK) is originally from southern Italy and dates back to Roman times. It produce a large green stem with flowering buds that can be either green or purple. In addition to the main flower head, broccoli also produces edible flowering side shoots.
Broccoli are generally grown as annuals and harvested in fall, although like other cabbages, an early summer harvest is also possible. However, it has a tendency to bolt easily with warm soil and its flavor is improved by cool weather. It doesn’t overwinter as well as other coles, so it’s really, in my mind, an autumn crop at heart.
Sprouting broccoli is a type of broccoli that produces small flower clusters instead of a large broccoli head. This type is grown to overwinter and harvest in spring, but is currently uncommon in the Pacific Northwest. It’s very well-adapted to our climate and provides a vegetable crop during a lean time of year (early spring is often called “the hungry gap”).
Also known as “Chinese broccoli”, gai lan is grown for its thick stems, flower buds, and leaves. It originated in China and is grown throughout southeast Asia as well. Gai lan is often better adapted to hotter climates and is a good early summer or fall crop. If summers are mild enough, it can be maintained throughout the season.
Broccolini is a natural hybrid between gai lan and broccoli that was developed in Japan in the 1990s to handle warmer weather than broccoli. Instead of harvesting the main stem and buds, the focus is on the side shoots. It is less cold-resistant but more heat-resistant, so best suited as an early summer or fall crop.
Other cole shoots
If left to grow into spring, all coles put out flower stems once the weather warms up. Kale, collards, cabbages, Brussels sprouts, etc.; all of these produce good, edible shoots.
These are often marketed with the name “raab”, such as “kale raab” or “cabbage raab”. Sounds fancy, but it’s a completely made-up term borrowed from “broccoli rabe”, another invented marketing name derived from “rapa”, the Italian word for “turnip”. Just call them shoots.
Meristem selections
Though its name has the word “flower” in it, cauliflower was really selected for its stems. In cauliflower, flowers never form; instead, the flowering stem continues to grow in a repeating manner, forming a cluster. This cluster is the vegetable we eat.
Cauliflower is thought to have originated in Cyprus during the Middle Ages or possibly earlier. They come in either white, yellow, green, or purple varieties, with white ones being the most common. In addition to the cauliflower head, the leaves of the plant are edible and flavorful.
Cauliflower grows better in the Pacific Northwest than many places. Our climate, especially near the coast, is ideal. There are fall and overwintering varieties; the overwintering varieties are ready to harvest during the “hungry gap” in spring.
In ‘Romanesco’ cauliflower, the repeating nature of the flowering stem’s growth can be seen more clearly than ever. The light green cauliflower head forms a striking fractal pattern. ‘Romanesco’ cauliflower is often mislabeled as a broccoli due to its green color.
Often marketed as “caulilini”, sprouting cauliflower varieties look like sprouting broccoli, and are selected for longer stems and smaller, looser heads.
Stem selections
In the case of kohlrabi, the main stem was selected, rather than the flower stems. Kohlrabi isn’t a root vegetable, it’s an enlarged, bulbous stem.
Its exact origins are unclear but it appears to have been developed in Europe during the Middle Ages. Today, it’s most popular in Germany, eastern Europe, and northern India. The name is German for “turnip cole”.
Kohlrabi is similar to broccoli or cauliflower stems. The bulb gets a woody inedible layer and needs to be peeled before eating. There are green and purple varieties; green varieties are the more common of the two. The leaves are also edible.
Kohlrabi can be grown as a spring or early summer crop, but smaller bulbs should be eaten as they can get too woody with warm weather. They also succeed as a fall and winter crop, getting sweeter with cold weather and overwintering very well.
