From Wikipedia (http://en.wikipedia.org/wiki/Chaya)

Chaya (Cnidoscolus chayamansa and Cnidoscolus aconitifolius) also known as Tree Spinach, is a large, fast growing leafy perennial shrub, native to the Yucatán Peninsula of Mexico. It somewhat resembles a vigorous hibiscus plant or the cassava plant. It is popular in Mexico and Central America as a leafy vegetable, cooked and eaten like spinach. It can grow to be 6 meters tall, but is usually pruned to about 2m for easier leaf harvest.

A USDA study in Puerto Rico reported that higher yields of greens could be obtained with chaya than any other vegetable they had studied. In another study chaya leaves were found to contain substantially greater amounts of nutrients than spinach leaves.

Chaya is easy to grow, very hardy, and suffers little insect damage. It is tolerant of heavy [soil] and has some drought tolerance. Propagation is normally by woody stem cuttings about 6-12 inches long, as seeds are produced only rarely. Early growth is slow to develop on the cuttings, so leaves shouldn't be harvested until the second year. Chaya leaves can be harvested continuously as long as no more than 50% of the leaves are removed from the plant. Enough leaves need to be left to guarantee healthy new plant growth.

Some varieties have stinging hairs and require gloves for harvesting. Cooking destroys the stinging hairs.

Chaya is a good source of protein, vitamins, calcium, and iron. However, raw chaya leaves are toxic as they contain a glucoside that can release toxic hydrocyanic acid. Cooking is essential prior to consumption to inactivate the toxic components. In this respect chaya is similar to Casava, which also contains toxic hydrocyanic glycosides and must be cook before being eaten.

Traditionally leaves are immersed and simmered for 20 minutes and then served with oil for 10 minutes or more will render the leaves safe to eat, as only 1 minute of boiling will destroy most of the HCN . Do not cook in aluminum cookware as a toxic reaction can result .

The stock or liquid the leaves are cooked in can also safely be consumed as HCN is volatilized during cooking.

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