Tetragonia is a genus of about 85 species of flowering plants in the family Aizoaceae, native to temperate and subtropical regions mostly of the Southern Hemisphere, in New Zealand, Australia, southern Africa and South America.
Plants of the Tetragonia genus are herbs or small shrubs. Leaves are alternate and succulent, with flowers typically yellow and small in size. Flowers can be axillary, solitary or fasciculate, greenish or yellowish in color and mostly bisexual. Fruit are initially succulent but become dry and woody with age. The genus name comes from "tetragonus", meaning "four-angled" and referring to the shape of the plants' fruits.
The best known species of Tetragonia is the leafy vegetable food crop, Tetragonia tetragonioides, commonly known as New Zealand Spinach, widely cultivated as a summer leafy vegetable. Some of the other species are also eaten locally, such as Tetragonia decumbens, commonly known as Dune Spinach, which is a local delicacy in its native southern Africa.
Growing Conditions and General Care
New Zealand Spinach is grown for the edible leaves, and can be used as food or an ornamental plant for ground cover. As some of its names signify, it has similar flavor and texture properties to spinach, and is cooked like spinach. Like spinach, it contains oxalates. Its medium to low levels of oxalates need to be removed by blanching the leaves in hot water for one minute, then rinsing in cold water before cooking. It can be found as an invasive plant in North and South America, and has been cultivated along the East Asian rim. It thrives in hot weather, and is considered an heirloom vegetable. Few insects consume it, and even slugs and snails do not seem to feed on it.
The thick, irregularly-shaped seeds should be planted just after the last spring frost. Before planting, the seeds should be soaked for 12 hours in cold water, or 3 hours in warm water. Seeds should be planted 0.2 to 0.4 inches (5 to 10 mm) deep, and spaced 6 to 12 inches (15 to 30 cm) apart. The seedlings will emerge in 10 to 20 days, and it will continue to produce greens through the summer.