By Glenn I. Teves, County Extension Agent, UH CTAHR
On Molokai, the summer heat can overwhelm many of the vegetables that grow well in the winter. Collards or collard greens can grow at a time of the year when local greens struggle and are in short supply. A primitive member of the cabbage family, it belongs to the “Acephala” group meaning “cabbages without a head.”
Collard is a corrupted term from the word “colewort” meaning “wild cabbage plant.” Native to the southern Mediterranean in an area called Asia Minor, a part of Turkey, it was carried in all directions and is popular in Portugal and Spain to the west, Bosnia, Montenegro, Croatia and Serbia to the east, and African and India to the south. The Spanish speaking countries call it Berza, while the Portuguese and Brazilians call it Couve.
More heat-tolerant than its northern cousin, kale, collard greens are a favorite of the southern U.S. introduced by African slaves, and an important part of their unique cuisine. Some collards are called kale, both known for their high nutritional, antioxidant and anti-cancer properties, but collards can be distinguished from kale by their large rounded, cabbage-like leaves. Like kale, collards can be grown as a perennial in Hawaii and enjoyed for years, while age will not affect its flavor.
Like other cabbages, it can also be salted or even fermented like sauerkraut or kim-chee to preserve them. Collards fit into the our local diet as an addition to stews, soups, saimin, and in stir fry dishes with bits of meat. Collards contain calcium oxalate, an irritant to some of our organs, and should be cooked before eating to break down this compound. Calcium oxalate, implicated with kidney stones through the accumulation and cementing of calcium into small stones, are found in many vegetables including kale, spinach, beets, chard, and others.
Collards are a durable plant but can face similar pests as its cabbage cousins, such as Aphids, Imported Cabbage Worm, and Green Garden Loopers, but can be controlled with organic insecticides such as Bacillus thurengiensis or Neem. In wet areas, plants are susceptible to Black Rot, a bacteria that can spread and maintain itself in plant material and seeds. Powdery mildew, a whitish fungus in the surface of leaves can cause early dieback of leaves in certain seasons, but some varieties are more tolerant to this disease than others.
There are many popular collard varieties. Hybrids include Flash, Hi Crop, Heavy Crop, Top Bunch, Bulldog, and Tiger, while open-pollinated varieties include Vates, Champion, Morris Heading, and Georgia. Based on a trial of commercial varieties in Florida, the most heat-tolerant and bolt-resistant were Champion, Vates, and Flash.
Closely related varieties, with large rounded leaves, include Couve Tronchuda, Walking Stick Cabbage, and Galega de Folhas Lisas. Walking stick cabbage or kale is a popular variety in Hawaii because it can be grown as a permanent addition to a subsistence garden. It can reach a height of 10 feet, and is propagated by chopping the stem in sections like sugarcane and sticking it in the ground. The leaves are readily available as a constant food source. This crop is a great addition to a subsistence garden.