Michelle Obama’s kitchen garden on the South Lawn of the White House merits a double brava!—apart from calling attention to the nutritional value of eating fresh, organically grown vegetables, it honors their global origins. We are not only a nation of immigrant peoples and cuisines. We are also a country of immigrant plants, trees, and vines. Mrs. Obama’s garden inevitably, if not intentionally, expresses that diversity, with its radishes, rhubarb, and spinach from Asia, its kale, broccoli, lettuce, and oregano from the Mediterranean, its fennel from India and Egypt, and its border marigolds from Mexico.
When European settlers first arrived in North America, they found an abundant garden. Blackberries, raspberries, and blueberries, which are planted about eight feet north of the White House vegetable patch, grew prolifically in the woods. The Indians gathered them from the wild, but they also cultivated corn and sweet potatoes, which had come from Latin America, as well as squash and beans, which they had bred from indigenous plants.
Plant improvement can result from advantageous mutations. It can also arise from sexual crossing, whereby the pollen from the stamens (the male sexual organ) in one plant penetrate the pistil (the female organ) in another, fertilizing it. Such crossing occurs all the time in nature, the pollen being carried by wind, insects, and birds. Like plant breeders since ancient times, the Indians improved their crops by selecting for reproduction the superior progeny produced by mutation or by natural pollination either within one plant variety or between two different varieties planted in proximity to each other. They were ignorant of the mechanism of sexual crossing, believing in cases of mixed varieties that the two somehow mingled their characters through the entanglements of their root systems.
No matter their misunderstanding: their breeding practices were effective. They planted the superior seed, selected superior plants from the next crop, and obtained improved varieties by repeating the process through successive generations. They introduced these varieties to the European newcomers, who were very glad to have them. In 1923, Lyman Carrier, an expert on the origins of American agriculture, noted that “no people anywhere in the world ever made greater strides in plant breeding than did the American Indians,” adding, “Our agriculture is at least one-third native American.”
However, most of the rest, like almost all the plants in the White House garden, have come from elsewhere on the planet. From the first Spanish arrivals, European conquerors and settlers supplemented the native fruits and edible plants with basic food from the Old World and the southern half of the new one, including wheat, rye, barley, and oats; lettuce, onions, cabbage, and asparagus; eggplant, cucumber, okra, and beets; carrots and cauliflower; celery and parsley; parsnips, peas, and turnips. They also imported pasturage grasses, such as alfalfa, clover, timothy, and bluegrass, to feed their livestock, a type of husbandry that the …