Collards – actually Collard greens – are the American English term for various loose-leafed cultivars of Brassica oleracea that have large, dark-colored, edible leaves. They are classified in the same cultivar group as kale and spring greens since they are genetically similar, and Collard greens are highly popular with “Southern” cooking.
The Collard plant is a biennial where winter frost occurs, and perennial in even colder regions. It is also moderately sensitive to salinity. Collard greens are valued for their thick, slightly bitter leaves that grow on an upright stalk that often reaches a height of 2 feet. They are tastier and more nutritious in the cooler months after the first frost. For best texture, the leaves should be picked well before the stalks grow to 2 feet. Age will not affect flavor, but fully mature leaves are thicker and require special attention when being cooked.
Fresh collard greens can be stored in the typical home refrigerator for up to 3 or 4 days. Once cooked, they can be frozen to be stored for a much longer time.
Collards are a very healthy food with good sources of vitamin C and soluble fiber, and contain multiple nutrients with potent anticancer properties. For people counting calories, 4 ounces of cooked collards contain only 46 calories. Collard greens are also a high source of vitamin K (the clotting vitamin), but should be eaten in moderation by individuals taking blood thinners.