Collard greens (Brassica oleracea; Acephala Group) are a large-leafed, dark green relative of the cabbage. They are related to kale and mustard greens as well, and are relatively mild, the flavor approximating a combination of cabbage and kale. Unlike the curly-leaved kale, collards have smooth leaves.
These greens are native to the Mediterranean region. Ancient Greeks and pre-Christian Romans cultivated this vegetable, and there is evidence that they have been grown in Britain for over 1,000 years. The first record of them in the United States dates back to the 1600s. Today, collard greens are widely cultivated in the American South, as well as Brazil, Spain, Portugal, regions of Africa, and other areas as well. The loose-leafed, nonheading plant is relatively hardy, tolerating frost and cold better than any of its cabbage cousins.
A 1 cup (190 g) portion of cooked collard greens has about 50 calories and is packed with nutrients. It is an excellent source of vitamins C, A, and K, as well as manganese and folate. In addition, this same serving will provide a good source of calcium, fiber, and beta-carotene, as well as vitamin E. Rich in nutrients and antioxidants, these greens are beneficial for supporting the immune system, the skin and bones, the eyes, and for aiding digestion.
Collard greens are available year-round — fresh, frozen, and canned. When choosing fresh ones, cooks should avoid any leaves that are wilted or discolored and select only those that are deep green and unblemished. The smaller the leaf, the milder its flavor and the more tender it will be.
This vegetable keeps better than other types of greens in the refrigerator, but they will grow bitter if they stand too long. Cooks should wrap unwashed leaves in damp paper towels and place in a resealable plastic bag in the crisper drawer of the refrigerator. They should be used within five days.
Because they have a tendency to be sandy, fresh greens should be washed thoroughly prior to cooking. An effective method of removing grit and sand is to trim the root ends from the stems and submerge the leaves in a bowl of water. A cook can use her hands to swish the leaves through the water, allowing the dirt to fall to the bottom. The leaves can then be put in a colander, rinse them with clean water, and replace the water in the bowl. This process should be repeated two or three times until no dirt is visible at the bottom of the bowl.
Before cooking, any tough stems or midribs should be trimmed off. The traditional Southern method of cooking is to slowly simmer the collard greens in water with a bit of salt pork for flavor, until they are very tender. Alternatively, collards can be simmered in broth, omitting the pork. Because they are so fibrous, it can take about 45 minutes to 1 hour for these greens to cook. Vinegar complements their bitterness and is often served alongside them as a condiment.