The Leafy Brassicas
The Brassicaceae is one of the most important families to the human food supply. The species Brassica oleracea represents most of the plants in this group though a few are of the species B. juncea and B. rapa, and the taxonomy can be a bit squirrely—only a big deal if you care about taxonomy.
Cauliflower and broccoli are also B. oleracea but those are dealt with in another post, since the edible portion of these crops are the flower buds.
This is an overview of the leafy members of this group which we use as greens, stems, and roots.
The leafy brassicas are eaten raw, pickled, and cooked. Some are spicy while others are mild. Most are green but some are white, yellow, purple, and/or red. There is a diversity of textures in this group—greens that are smooth, coarse, bumpy, leathery, delicate…giving our food supply a diversity of greens to choose from.
This group does not include the lettuces which are often confused with leafy brassicas but are of an entirely different genus and family. Arugula is also handled in a separate section, though from the same family (but different genus). And there are a multitude of other specialty greens that are not brassicas.
These greens are all cool-season crops in our climate. The leafy brassicas are planted starting in the fall and throughout the cool season. They can be planted as seed directly into the ground as soon as August or September and thinned out as they grow, or they can be obtained as starts from plant nurseries, usually available starting in October. Make sure you give these plants the proper space to grow if you want a developed head or rosette. Tightly sewn plants will be stunted—though this is a style of growing greens and perfectly acceptable. Find out the approximate amount of space your variety takes up. If you are planting from seed, thin out seedlings as you go along—the seedlings you pull can be added to your salad that day as a microgreen. Most of these crops can be planted throughout the season, most even planted into the spring until the weather gets so warm that the plants begin to bolt (go to flower/seed). Some varieties can go further into spring or even early summer than other varieties.
When you plant from seed, thin out as you go along. Remember that especially with head-forming crops, many greens need space to develop.
When planting, pay attention to the “days to maturity” rating each crop have. Most reputable seed companies will list this on their packaging. If you got your plant from a nursery, you will have to look up the variety on google and remember that “days to maturity” is the number of days from seed germination, so there will be guess work. Most times
The leafy brassicas do best in part to full sun, with moderately enriched soil, good drainage, and even moisture. Most love the cool weather, and some even improve in flavor with cold and/or frost. Feeding with balanced organic fertilizer is optimal. These crops are generally one of the easiest to grow—they take up a predictable amount of space and the biggest problem is usually just trying to keep them from bolting when the weather gets warm.
CABBAGE
Cabbage (comprising several cultivars of Brassica oleracea) is usually a head-producing crop that takes some time to develop. Of all the leafy brassicas, this crop should be planted early, and given enough time to develop. This crop you generally harvest when it reaches its peak maturity, rather than harvesting throughout the season, as you do with kale. Cabbage keeps in the fridge for a long time, so when you harvest, you have time to think about how you will manage your bounty. On these crops, definitely pay attention to the amount of days to maturity you need. With Cabbages, you want to look for “heat tolerant” varieties with shorter days. You can grow the crops that require longer days, but you can’t wait too long before you plant, and it is better to plant before the winter equinox (December 21). If you plant afterward, definitely pick the shorter-day varieties. Cabbages come in green and red varieties in color, some heirlooms have multiple colors. They also come in regular or savoy: savoy cabbage has a bumpy texture like some kales have, while regular cabbage are smooth. And finally, some cabbages are the “oxheart” variety, where the head doesn’t quite form at the top and the final product is not a round head, but more of a pointy one. Even with the smaller cabbages, make sure you give these crops space—they take up a good amount of it.
Kale
Kale (Brassica olderacea, acephala group) has become very popular in recent years, but for those of us who garden, it’s not a hipster vegetable, but a stable food. Kale has a greener flavor than cabbage, and can be harvested perpetually as the season progresses. This is a nice convenience because you can just pick what you need throughout the season rather than just harvesting the whole thing when the plant reaches maturity. Compared to cabbage, kale comes in a lot more variety—of leaf shapes, colors, textures…some cabbage even become tree-like, like the dino kale. As with cabbage, give these guys room to grow. Sometimes kale is found in a “greens mix” and is intended to be harvested while young rather than growing out to mature sizes.
Collards
Southern cuisine (which is to say, soul food) isn’t complete without collards (Brassica olderacea, acephala group). At first glance, you might think this is a boring food. But the variety of ways in which collards have been used in soul food is mind-boggling. Collards might not be available in the array of leaf-types or colors that kale is, but the array of finished products that this durable green can produce makes up for that. Most collards grow in something of a rosette. A few varieties form a cabbage-like head, though not the perfect ball that cabbage is known to produce. Some will form trunks like many kales form, and be tree-like. Like kale, collards can be picked as needed, working from the outside, in. Collards are best planted early in the season, but at least plant in time for the plant to mature into the larger-sized crop that it’s famous as.
Brussels sprouts
Brussels sprouts, a member of the gemmifera group of cabbages (Brassica oleracea), first appeared in northern Europe during the 5th century, later being cultivated in the 13th century near Brussels, Belgium, from which they derived their name. The Brussels sprout is grown for its edible buds that form along the trunk of the main plant. In its seedling stage and early development, the plant closely resembles the common cabbage, but the main stem grows to a height of 2 to 3 feet, and the axillary buds along the stem develop into small heads (sprouts) similar to heads of cabbage but measuring only 1 to 1.5 inches in diameter. These should definitely be planted before the winter equinox (December 21) for best results. There are green and purple varieties, as well as open-headed sprout varieties.
cow cabbage
Cow cabbage (Brassica oleracea longata) plant is known by many names—often called by many other names: Jersey kale, waking stick kale or cabbage, long jack, or chou à vacque. This crops hails from the Caribbean where it was originally grown primarily for livestock feed, and for the “walking sticks” that persist after the crop has grown. This crop has the capability of reaching up to 20’ tall though it is usually much shorter. The earlier you plant in the season, the taller your plant will get. These can sometimes last into the summer much longer than other crops and can even perennialize. Cut the lower leaves as you need. The trunk develops as the plant grows. Instead of feeding cattle, these days many people use the lower leaves to feed smaller animals like chickens or rabbits.
Kohlrabi
Kohlrabi (Brassica oleracea, gongylodes group) is a strange vegetable, indeed. It can be eaten raw or cooked. Edible preparations are made with both the stem and the leaves. The first European written record is by the botanist Mattioli in 1554 who wrote that it had “come lately into Italy”. By the end of the 16th century, kohlrabi was being grown in Austria, Germany, England, Italy, Spain, Tripoli and parts of the eastern Mediterranean. Kohlrabi has been created by artificial selection for lateral meristem growth (a swollen, nearly spherical shape). It has received a lot of attention lately amongst those who like to make kimchi. There are purple and white varieties.
Chinese cabbage
Chinese cabbage in many cases does not include Bok Choy, discussed below, but are much more substantial and have a distinct flavor. The two are different subspecies, this one being Brassica rapa subsp. pekinensis. Chinese cabbage is also known as napa cabbage. Whether it's encountered in a Chinese stir-fry, pickled in Korean kimchee or used in Japanese soups or sukiyaki, Chinese cabbage plays a principal role in Asian cuisine. Its mild delicate flavor makes it a welcome addition to a salad or sandwich. In Asia, the vegetable is an important source of nutrition in winter. It is typically pickled in Japan and Korea and dried in China to be included in soups during the cold season. There are three main styles of Chinese cabbage: barrel-shaped, cylindrical (also called Michihili), and loose-leaf or fluff top. It’s most optimal to start before the winter equinox, particularly for the heading types. Like headed cabbage, there will be outer layers of leaves that aren’t part of the head. These can be tied up if you want to blanch the inner head.
Bok Choy/Pak Choi
This is a different subspecies than Chinese cabbage and is a very different vegetable (this being Brassica rapa subsp. chinensis). Varieties do not form heads and have spoon-shaped green leaf blades with lighter bulbous bottoms instead, forming a cluster reminiscent of mustard greens. Bok Choy simply means “white vegetable” and to be specific to this crop you should refer to it as siu bok choy (Cantonese, for "small white vegetable”); as opposed to dai bok choy ("big white vegetable"). This graceful vegetable with Chinese origins has spread throughout Asia and beyond, developing a wide range of varieties. The most typical bok choy features dark green leaves atop white upright stems. Stems vary considerably in thickness and shape, and in some varieties they are green. There are specialty bok choy varieties that have frilly leaves to light yellow-green color. The slight mustardy flavor of this vegetable makes it a delightful addition to stir-fries, soups, noodle and meat dishes, and salads, if the young leaves are used. In China, the coarser leaves are often pickled. Some Chinese cooks also dip the leaves in boiling water and hang them out to dry in the sun for several days. Drying enables this highly perishable vegetable to be stored for winter months. Asian cooks use the entire plant at many stages of development. Bok Choy comes in an array of colors (of both stem and leaf), as well as in a variety of sizes, large to dwarf. A few have variations in leaf texture and growth form.
Tatsoi
Tatsoi (Brassica rapa subsp. narinosa or Brassica rapa var. rosularis) looks like a flat bok choy. Many people put it into that category. But this is an altogether different subspecies than bok choy or Chinese cabbage and deserves its own category. The name comes from Cantonese translating to “drooping vegetable". This crop originated along the Yangtze River. The plant has naturally has dark green spoon-shaped leaves which form a thick, flat rosette. It has a soft creamy texture and has a subtle yet distinctive flavor. There are many new variations of this crop which include different colors and textures. Tatsoi is used in the same ways that bok choy is used.
Komatsuna
An unlikely relative of the turnip family, komatsuna (Brassica rapa var. perviridis) is a large leafy green grown almost exclusively in Japan, Taiwan and Korea. The name 'komatsuna' means 'greens of Komatsu' in Japanese, a reference to the village of Komatsugawa in Edogawa, Tokyo, where it was heavily grown during the Edo period. It was named by Tokugawa Yoshimune, the eighth shogun, who visited Edogawa in 1719 for hunting and stopped at the local Katori Shrine for lunch. The shrine priest served him soup with a rice cake and the local leaf vegetable. The shogun was impressed by the flavor of the vegetable so much and named it komatsuna, after the nearby Komatsu River (which gives Komatsugawa its name). Till this day, the Shin-Koiwa Katori Shrine offers komatsuna to the deities on New Year's Eve. People who come to the shrine to pray on New Year's Day are also given komatsuna for good luck in the new year. Since the days of the shogun, komatsuna has been bred to have a sweeter taste. The old variety thought to have been served to the shogun is not widely available. That variety is called Goseki bansei. It grows faster and has bigger but fewer leaves than ordinary komatsuna, and a strong, spicy flavor. Komatsuna has a fresh, sweet taste and a crunchy texture. It is a very versatile vegetable and can be eaten raw, pickled, stir-fried, boiled, used fresh in salads, or added to soups. It is popular in soups as it can stay firm after being simmered.
Mizuna
Mizuna, a cultivar of Brassica rapa var. niposinica, has a flavor that has been described as a piquant, mild peppery flavor, slightly spicy, but less so than arugula and is most often eaten in salads in the west. It is also used in stir-fries, soups, pickled, and nabemono (Japanese hot pots). This crop has been cultivated in Japan since ancient times. Mizuna was successfully grown in the International Space Station in 2019. In Japan, Mizuna is one of several vegetables known as ‘Kyo yasai’ or ‘Kyo-no-dento-yasai’ which refers to heirloom vegetables traditionally grown in Kyoto. Mizuna was grown in the area around the Mibu-Dera temple in the southern region of Kyoto, where natural springs helped with irrigation efforts and kept the fields wet for the greens to thrive. In Japan today, Mizuna is still used in cooking and is most commonly pickled in a simple brine of salt or with other sea vegetables. Many new hybrids usually aim at tenderness and color.
Mibuna
Mibuna (Brassica rapa var japonica) is an unusual Japanese green that requires very little preparation and originates from the town of Mibu, in Japan. Plants grow to about one foot tall and produce tight clusters of long, narrow, rounded dark green leaves. Enjoy its light mustard flavor in a salad or as a side dish green, lightly cooked and seasoned. The leaves are also excellent for pickling. It is similar to mizuna, but with a stronger, more interesting flavor.
Mustard Greens
These are the broadleaf mustards (Brassica juncea, integrifolia group)—the specialty mustards like mizuna, mibuna, and wrapped heart are discussed separately. For a leafy green that is rarely called for in western recipes, leafy mustards are diverse, prolific and interesting. In the Far East, the most common use for mustards is pickling. They are also common in soups and stir-fries in both China and Japan, as well as salads, for the milder varieties. The leaves are used in African cooking, and all plant parts are used in Nepali cuisine, particularly in the mountain regions of Nepal, as well as in the Punjabi cuisine in the northern part of the Indian subcontinent, where a dish called sarson da saag (mustard greens) is prepared. Some varieties are leafy like kale or spinach, while others form a head, more like a cabbage. Colors range from reddish to purple to the more common green. You can harvest and use the entire plant for pickling or cooking, or let it go to seed and make your own mustard in the blender using the seeds, some vinegar, spices and water (you have to grow a considerable amount of plants to achieve this). Baby leaf mustards are making quite an inroad into Western cuisine, particularly in salads, where they add an appetizing flavor and texture. The delicately spiced greens are striking in appearance, particularly the varieties with lacy or frilly leaves. Their colors, which range from bright light green to garnet red, also add appeal to salads or alongside a gourmet dish. These baby greens grow quickly, and young leaves can be harvested on the lower part of even a mature plant. If grown crowded, like other greens, mustard greens will not develop into full size, but be small and tender. If you want the plant to develop, give each variety the space they need.
Wrapped Heart & horned Mustard
Stem mustards are a group of mustards
Root mustards (Brassica juncea, subsp. tsatsai) are grown for their thickened stems or midribs, which are most often used for pickling. Zha cai, which has a knobby, fist-sized, swollen green stem, is famous as a Szechuan preserved vegetable, and a staple in many regions. Dan dan noodles get their distinctive flavor from this preserve. The stem is first salted, pressed, and dried before being rubbed with hot red chili paste and allowed to ferment in an earthenware jar. This preservation process is similar to that used to produce Korean kimchi. Kekkyu tekana (wrapped heart) and horned mustard are used in similar ways.
Root mustard
Root mustards are considered a newer development in crops, though many cultures must have used the roots that developed on various mustards from around the world. Root mustards are considered in the napiformis group of Brassica juncea. The variety “golden frill” is the easiest to find. You can harvest the leaves while the root develops over time. As with many root crops, you may be careful about adding too much nitrogen, and you will want to emphasize phosphorus.