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Leaves to Live By:
Perennial Leaf Vegetables

by Craig Elevitch
AgroForester
PO Box 428, Holualoa, HI 96725 USA
Tel: 808-324-4427, Fax: 808-324-4129
agroforestry.net
Copyright 1998

Landscaping with Edible Perennials There are basically two types of gardeners: the “master gardener” type who genuinely delights in the detailed tasks of garden management and the “lazy” gardener who enjoys harvesting but who experiences other garden activities as drudgery. I belong to the latter category. For years I’ve been striving for the generous results of the master gardener without the continual effort. The solution was to abandon the idea of building my garden around familiar annuals such as lettuce, spinach, and peas. This happened when I discovered a whole group of perennial plants that have edible leaves, stems and often other parts. These are known as “perennial vegetables,” or “leaf spinaches.” Instead of annual garden beds, these leafy plants adorn the house and its various pathways. Anybody who has not seen many of these perennial vegetables before might think that they were unusual, yet highly appealing, ornamentals. Best of all, these perennials provide edible leaves nearly year-round, in a quantity and diversity that I could ever hope for from a conventional garden of annuals. Most of my formerly neglected annual garden space is now filled with thriving perennials which yield copious amounts of edible leaves but require almost no tending. Apart from being ornamental and edible, perennial vegetables can serve other functions around the house such as view screens (Pacific spinach, moringa), ground covers (sweet potato, bitter melon), and edge plants as a barrier to weeds (sissoo spinach, garlic chives). Many of these plants have medicinal as well as culinary utility (comfrey, moringa). One of the satisfying parts of eating perennial vegetables has been to become aware of the many plants growing in my bioregion which have edible parts. There are thousands of plants with edible parts, and hundreds which people have cultivated over the millennia. Most modern gardens have tended to focus on just a very few leafy edible species, most of which are short-lived annuals, such as lettuce, cabbage, and common spinach. Adding lesser-known perennials to the garden contributes to diversity in the ecosystem and the diet. Harvesting Perennial Vegetables For most perennial vegetables, the best part to eat is the tender growing shoot or tip which includes the young leaves which have not yet matured and the soft growing stem. shoots are favored for eating because they are sweeter and more tender than older growth. The mature leaves can often also be eaten, but require longer cooking times and can still be tough eating. The way to harvest shoots is to simply snap off the tender stem where it naturally breaks, leaving the more mature and fibrous stem and leaves. The plant then regrows more stems, and production of shoots is multiplied! If the plants receive sufficient water, growth of new shoots continues throughout the year in subtropical and tropical climates, and throughout the growing season in temperate climates. Adding Perennial Vegetables to the Diet As I began adding more leafy perennials to my diet I began wondering how much I should be eating. Just as with any food, too much is not good. Most plants have nutritive as well as non-nutritive effects on the body. In other words, eating too much can have toxic effects or upset digestion. The toxic effects can be moderated by including small amounts of a wide variety of leafy vegetables in the diet. Even though a plant’s leaves are known to be edible, I found it a good idea to start with just 1-2 leaves to see how my system reacts. It also gives my palate some time to familiarize itself with the new taste sensations. As I became familiar with a vegetable, I learned how much felt good to eat. For most plants, about 10 shoots, a handful (1/2 cup cooked), is a good amount for me for one meal. Cooking Usually Necessary Plants from the tropics have evolved even more toxins as a defense against predators than those from temperate climates. For example, the leaves of Tahitian taro (and other taro species) contain high amount of calcium oxylate crystals that are highly irritating to mouth and throat. Cassava leaves often contain substances which can release highly toxic hydrocyanic acid. That is why many plants of sub-tropical or tropical origin require cooking in order to eat them. Cooking dispels or denatures the harmful toxins, and makes the remaining portion safe to eat. Because much of the nutrients and enzymes are destroyed in the cooking process, it is best to cook for the shortest time possible while still removing toxic effects. References such as Bailey (1992) give recommendations for cooking times and methods for many popular subtropical/tropical perennial vegetables. Knowledge of edibility of plants has been developed slowly over a long period of time. Experts in the edible plants recommend strongly against testing an unknown plant yourself for edibility. Such trials can be toxic to the system and/or fatal. There are some excellent reference books available (see list below). I have found books, plant lovers, and experienced ethnobotanists to be the best source for knowledge of edible plants. Also, I have discovered that there are a surprising number of perennial vegetables available which have been selected for their vigorous growth, favorable taste, lower content of bad tasting or toxic substances, and beauty. Once established, plantings of perennial vegetables around the house can provide an abundance of leafy vegetables for years. A short list of favorite and abundant perennial vegetables. Many subtropical and tropical perennials can be grown as annuals in temperate regions. Tropical Species Common Name Botanical Name Edible Parts Uses/functions katuk Sauropis androgynus leaf tips, leaves hedge sweet potato Ipomoea batatas leaf tips, leaves, tuber ground cover cassava Manihot esculenta leaves, tuber hedge, privacy break Pacific spinach Abelmoschus esculentus leaf tips, leaves privacy break Tahitian taro Xanthosoma braziliense leaves hedge chaya Cnidoscolus chayamansa leaf tips, leaves Okinawan spinach Gynura crepioides leaf tips, leaves ground cover Ceylon spinach Basella rubra leaf tips, leaves ground cover Sissoo spinach Alternanthera sissoo leaves ground cover, barrier moringa Moringa oleifera, M. stenopetala leaf tips, leaves hedge, trellis Subtropical Species Common Name Botanical Name Edible Parts Uses/functions winged bean Psophocarpus tetragonolobus leaf tips, leaves, pods, tuber bitter melon Momordica charantia leaf tips, leaves, fruit ground cover pumpkin Curcurbita moschata leaf tips, flowers, fruit ground cover (large areas) garlic chives Allium tuberosum leaves, flowers weed barrier chili peppers Capsicum frutescens leaf tips, fruit hedge water cress Nasturtium officinale shoots water’s edge chayote Sechium edule leaf tips, fruit ground cover (large areas) Temperate Species Common Name Botanical Name Edible Parts Uses/functions comfrey Symphytum officinale young leaves weed barrier perennial kale Brassica oleracea leaf tips, leaves hedge chicory Cichorium intybus leaf tips, leaves, flowers sorrel Rumex acetosa leaves, flowers lamb’s quarters Chenopodium album leaf tips, leaves, flowers References and further reading: Martin, Franklin W., R. Ruberté, and L. Meitzner. 1998. Edible Leaves of the Tropics, 3rd Edition. Available from ECHO, 17430 Durrance Rd., N. Ft. Myers, FL 33917, U.S.A., echo@echonet.org, http://www.echonet.org Facciola, Stephen. Cornucopia: A Source Book of Edible Plants. 1990. Kampong Publications, 1870 Sunrise Drive, Vista, CA 92084 USA. International Institute of Rural Reconstruction. 1993. The Bio-Intensive Approach to Small-Scale Household Food Production, IIRR, Room 1270, 475 Riverside Dr., New York, NY 10115 Martin, Franklin W.. 1994. Plants for Use in Permaculture in the Tropics, Yankee Permaculture, P.O. Box 672, Dahlonega, GA 30533-0672 ADAP Project, Pacific Islands Farm Manual. 1994. ADAP Project, Tropical Energy House, University of Hawaii, Honolulu, HI 96822 Bailey, John M.. 1992. The Leaves We Eat, South Pacific Commission, B.P. D5, Noumea Cedex, New Caledonia