A bundle of collard greens
|Cultivar group||Acephala Group|
|Cultivar group members||Many; see text.|
Collard greens (collards) are various loose-leafed cultivars of Brassica oleracea, the species which also contains vegetables including cabbage (Capitata Group) and broccoli (Botrytis Group). Collard greens are part of the Acephala Group of the species, which includes kale and spring greens.
The plants are grown for their large, dark-colored, edible leaves and as a garden ornamental, mainly in Brazil, Portugal, the southern United States, many parts of Africa, the Balkans, northern Spain and in northern India. They are classified in the same cultivar group as kale and spring greens, to which they are genetically similar. The name "collard" is a corrupted form of the word "colewort" (the wild cabbage plant).
The plant is also called "couve galega" in Portugal, "couve" in Brazil, "couve portuguesa" (among several other names) in Cape Verde, "berza" in Spanish-speaking countries, "col" in Colombia, "raštika" in Bosnia and Herzegovina and Croatia and "raštan" in Montenegro and Serbia. In Kashmir valley, it is called "haakh". In Tanzania and Kenya it is more commonly known by its Swahili name, "sukuma wiki", and is often confused with kale. In New Zealand, it is called "dalmatian cabbage".
The cultivar group name Acephala ("without a head" in Greek) refers to the fact that this variety of B. oleracea does not have the usual close-knit core of leaves (a "head") like cabbage. The plant is a biennial where winter frost occurs, and perennial in even colder regions. It is also moderately sensitive to salinity. It has an upright stalk, often growing up to two feet tall. The plant is very similar to kale. Popular cultivars of collard greens include 'Georgia Southern', 'Morris Heading', 'Butter Collard' (or couve manteiga), and couve tronchuda.
Cultivation and storage
The plant is commercially cultivated for its thick, slightly bitter, edible leaves. They are available year-round, but are tastier and more nutritious in the cold months, after the first frost. For best texture, the leaves are picked before they reach their maximum size, at which stage they are thicker and are cooked differently from the new leaves. Age does not affect flavor. Flavor and texture also depend on the cultivar; the couve manteiga and couve tronchuda are especially appreciated in Brazil and Portugal.
Fresh collard leaves can be stored for up to 10 days if refrigerated to just above freezing (1°C) at high humidity (>95%). In domestic refrigerators, fresh collard leaves can be stored for about three days. Once cooked, they can be frozen and stored for greater lengths of time.
|Nutritional value per 100 g (3.5 oz)|
|Energy||137 kJ (33 kcal)|
|Dietary fiber||4 g|
|Vitamin A equiv.||
|Pantothenic acid (B5)||
|Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
Like kale, collard greens are very high in vitamin K. They are excellent sources (20% or higher of the Daily Value) of vitamin A, vitamin C, and manganese, and moderate sources of calcium and vitamin B6 (table). A 100 g serving of cooked collard greens provides 33 calories, is 90% water, 3% protein, 6% carbohydrates and less than 1% fat (table).
Southern United States
Collard greens are a staple vegetable of Southern U.S. cuisine. They are often prepared with other similar green leaf vegetables, such as kale, turnip greens, spinach, and mustard greens in "mixed greens". Typical seasonings when cooking collards consist of smoked and salted meats (ham hocks, smoked turkey drumsticks, pork neckbones, fatback or other fatty meat), diced onions, vinegar, salt, and black, white, or crushed red pepper, and some cooks add a small amount of sugar. Traditionally, collards are eaten on New Year's Day, along with black-eyed peas or field peas and cornbread, to ensure wealth in the coming year. Cornbread is used to soak up the "pot liquor", a nutrient-rich collard broth. Collard greens may also be thinly sliced and fermented to make a collard sauerkraut often cooked with flat dumplings.
Tanzania and Kenya (East Africa)
Collard greens are known as "sukuma wiki" in Tanzania and Kenya.
In Congo, Tanzania and Kenya (East Africa), thinly sliced collard greens are the main accompaniments of a popular dish known as "sima" or "ugali" (a maize flour cake).
Sukuma wiki is mainly lightly sauteed in oil until tender, flavoured in onions and seasoned with salt and is served either as the main accompaniment or as a side dish with preferred meat (fish, chicken, beef, pork).
Brazil and Portugal
Thinly sliced collard greens are also the main ingredient of a popular Portuguese soup, caldo verde (green broth). For this broth the leaves are sliced into strips, 2 or 3 mm wide (sometimes by the grocer or market vendor, with a special hand-cranked slicer) and added to the other ingredients 15 minutes before it is served.
In Kashmir Valley, collard greens are included in almost every meal, with both leaves and roots consumed. Leaves in the bud are harvested by pinching in early spring when the dormant buds sprout and give out tender leaves. Also, seedlings of 35–40 days' age, as well as mature plants, are pulled out along with roots from thickly sown beds. When the extending stem bears alternate leaves in quick succession during on-season, older leaves are harvested periodically. Before the autumn season, the apical portion of stem is removed along with the whorled leaves. It is called haak there.
The roots and the leaves may be cooked together or separately. A common dish is haak rus, a soup of whole collard leaves cooked in water, salt and oil along with many other spices, usually consumed with rice. The leaves are also cooked along with meat, fish or cheese. In the winter, collard leaves and roots are fermented to form a very popular pickle called haak-e-aanchaar.
Pests of collards
The sting nematode Belonolaimus gracilis and the awl nematode, Dolichodorus spp. are both ectoparasites, capable of injuring the roots of collards. Root symptoms include, stubby or coarse roots that are dark at the tips while shoot symptoms include, stunted plants, premature wilting and chlorosis (Nguyen and Smart, 1975). Another species of the sting worm: Belonolaimus longicaudatus was shown to be a pest of collards in Georgia and North Carolina (Robbins and Barker, 1973). B. longicaudatus has been shown that to be devastating to seedlings and transplants. As little as 3 nematodes/100g of soil when transplanting can result in significant yield losses on susceptible plants. They are most common in sandy soils (Noling, 2012).
The stubby root nematodes Trichodorus and Paratrichodorus attach and feed near the tip of the tap roots of collard greens. The damage caused prevents proper root elongation leading in tight mats that could appear swollen, therefore resulting in a "stubby root" (Noling, 2012).
Several species of the root knot nematode Meloidogyne spp. are hosted by collards these include: (M. javanica, M. incognita and M. arenaria. Second stage juveniles attack the plant and settle in the roots. However, infestation seems to be at lower populations compared to other cruciferous plants. Root symptoms include deformation (galls) and injury that prevent proper water and nutrient uptake. This could eventually lead to stunting, wilting and chlorosis of the shoots (Crow and Dunn, 2012).
The false root knot nematode Nacobbus aberrans has a wide host range of up to 84 species including many weeds. On Brassicas it has been reported in several states including Nebraska, Wyoming, Utah, Colorado, Montana, South Dakota, Kansas (Manzanilla- López et al., 2002). As a pest of collards, the degree of damage is dependent upon the nematode population in the soil.
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- Media related to Brassica oleracea var. viridis at Wikimedia Commons