Perennial Leaf Vegetables
by Craig Elevitch (see bio at bottom), originally published in the Permaculture International Journal, #61 Dec-Feb 1997 page 31
There are two types of gardeners as I see it: 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 have been striving for the generous results of the master gardener without the continual effort. That’s what permaculture is about for me – abundant results for minimal effort.
The solution for me was to abandon the idea of building my garden around familiar annuals such as lettuce, spinach and peas. This happened when I learned about 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 hadn’t seen many of these perennial vegetables before might think that they were just unusual (but highly appealing) ornamentals. Best of all, I can forage from these perennials with edible leaves nearly all year round and get all the 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 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 for me was becoming 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.
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 favoured 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.
How Much Should You Eat?
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 familiarise itself with the new taste sensations. As I become familiar with the vegetable, I learn what amount felt good to eat. For most plants, about 10 shoots, a handful (1/2cup cooked), is a good amount for me for one meal.
Plants from the tropics have evolved even more toxins as a defence 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 sub-tropical/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. 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 is a surprising number of perennial vegetables available which have been selected for their vigorous growth, favourable taste, lower content of bad tasting or toxic substances, and beauty. Once established, planting of perennial vegetables around the house can provide an abundance of leafy vegetables for years.
A short list of favourite and abundant perennial vegetables. Many sub-tropical and tropical perennials can be grown as annuals in temperate regions.
Shoots, leaves, pods
Hedge, privacy break
ground cover, barrier
|Shoots, leaves, pods, tuber
Shoots, leaves, fruit
Shoots, flowers, fruit
Ground cover (large areas)
Ground cover (large areas)
Shoots, leaves, flowers
Shoots, leaves, flowers
Craig Elevitch is based in Hawaii and has been working for island resource self-sufficiency since 1989. He directs Agroforestry Net, a nonprofit educational organization dedicated to empowering people in agroforestry and ecological resource management. The organization’s internationally recognized publications have guided thousands of readers in becoming more proficient in ecological food production, agroforestry, and permaculture. Craig edits The Overstory, a monthly agroforestry journal with over 8,000 subscribers in 185 countries. His books include Agroforestry Guides for Pacific Islands (2000), The Overstory Book: Cultivating Connections with Trees (2004), and Traditional Trees of Pacific Islands: Their Culture, Environment, and Use (2006), all of which promote diverse agricultural systems that produce abundant food and other resources. Further information and free downloads at Agroforestry.net.