Common name: Chaya

Chaya, or Mayan Spinach, is a shrub or small tree native to Central America, with its natural range extending from the Yucatan Peninsula in Mexico south to Guatemala and Belize. It is now cultivated in East Africa, Southeast Asia, the Philippines, Australia, South America, and the Caribbean, mainly as a home-garden vegetable.

There are two known subspecies, one of which (subsp. chayamansa) is cultivated for its leaves, which are cooked as a vegetable. The other (subsp. aconitifolius) is the wild form. Although sometimes also cultivated, the leaves of the wild form are covered in hairs that are an irritant to the skin.

The two subspecies also have different flowering and seeding habits, with the cultivated form seldom, if at all, producing seed. In contrast, the wild form freely produces viable seed, which contributes to its status as a weed. For this reason, only the cultivated form is described here.

It can grow into a small tree up to 6 m (20 ft) tall with a densely branched, rounded crown. However, it is more typically a shrub under 3 m (10 ft) and comes in different varieties, mainly distinguished by leaf size and shape. The stems are soft-wooded and exude a milky sap when wounded.

The leaves are large, up to 30 cm (12 in) long, nearly as wide, deep green and come in various shapes, ranging from shallow to deeply lobed and from slightly to strongly toothed on the margins, depending on the variety. Each leaf is borne on a long leaf stalk resembling those of Cassava (Manihot esculenta), a close relative. Some varieties have hairs that irritate the skin, but they are much smaller and fewer than on the leaves of the wild form and are mostly limited to the leaf stalk.

The flowers are small, white, and either female or male, borne together in clusters on long flower spikes. They bloom on and off throughout the year but are at their fullest in summer, which coincides with the rainy season in its native range. The fruit that follow are few in number, rarely mature to produce seed, and any seed produced is usually not viable.

Edible uses

Cooked vegetable - The leaves are harvested and cooked as a vegetable, though they must be cooked for at least a few minutes first, as they contain cyanogenic glycosides - a poison also found in Cassava (Manihot esculenta) and uncooked bamboo shoots - that evaporate during cooking and are not retained in the cooking liquid or sauce. Because they need this extended cooking time, they aren't well suited to quick stir-frying and are best used in stews, casseroles, and soups. Unlike spinach, they shrink very little when cooked and have a firm, cabbage-like texture, flavour, and good nutritional value.

Environmental uses

Hedge plant - In home gardens, Chaya is sometimes kept as a hedge and trimmed to 2 m (7 ft) or shorter, to make it easier to harvest the leaves, which can be harvested year-round provided no more than half are removed at a time, allowing the plant to keep growing and remain productive.

Health uses

The leaves are high in protein, reportedly approaching 6% of their dry weight, and are also a good source of the following:

Phosphorus
​Iron
​Vitamin B1 (Thiamine)
​Vitamin B2 (Riboflavin)
​Vitamin B3 (Niacin)​

Vitamin C - Present at about 165 mg per 100-gram serving.

Calcium - About 199 mg per 100-gram serving.

Climate

Grows naturally in sub-humid to humid subtropical and tropical lowland climates, generally frost-free areas with annual lows of 16 to 25°C, annual highs of 25 to 35°C, annual rainfall of 1000 to 2500 mm and a dry season of 2 to 7 months.

Growing

New plants are mostly started from cuttings, as seeds are not readily available. Cuttings of one- to two-year-old wood from selected varieties have produced good results. Cuttings measuring 15 to 30 cm (6 to 12 in) are dried in the shade for about a week before being planted. Because the wood is soft, it is susceptible to fungal attack in humid conditions, and drying the cuttings before planting helps prevent this problem. For this reason, the cuttings are never placed in water or wetted before planting.

Performs well on a wide range of soils, though is most productive on rich, free-draining loam and sand soils of a moderately acid to slightly alkaline nature, generally with a pH of 5.5 to 8.0 and on sites with full to partial sun exposure. Plants grown under partial sun exposure tend to produce leaves that are more tender than those under full sun. It is moderately tolerant of slow-draining or waterlogged soils.

Leaf-eating insects usually do not attack the leaves, which is often a challenge when growing other spinach-like plants for their leaves.

Commonly cultivated varieties include 'Chayamansa' and 'Redonda'.

Problem features

The leaves contain a cyanogenic glycoside, a cyanide-type poison also found in Cassava and uncooked bamboo shoots. Stinging hairs may be present on the leaves and leaf stalks of some varieties.

Books

• Francis, J. K. and Liogier, H. A. 1991, Naturalized exotic tree species in Puerto Rico, General technical report SO-82, USDA Forest Service, Southern Forest Experiment Station, New Orleans

• Gargiullo, M. B & Magnuson, B. L. & Kimball, Larry D. 2008, A field guide to plants of Costa Rica, Oxford University Press, Oxford

• National Research Council (Board on Science and Technology for International Development) 1975, Underexploited tropical plants with promising economic value, National Academic Press, Washington D. C.

• Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

• Schubert, T. H. 1979, Trees for urban use in Puerto Rico and the Virgin Islands. U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans

• Sterling, D. 2014, Yucatán : recipes from a culinary expedition, First edition, Austin, TX University of Texas Press