From A to Z, p. 58

KATUK (Sauropus androgynus) is one of the staple vegetables in Borneo, where it is sometimes grown as an edible hedge. It is one of our favorite summertime greens at ECHO. All greens, whether cooked or raw, are important nutritionally and can be tasty in various dishes. However, few are known especially for their unique taste. Katuk is delicious; after chewing a raw leaf or stem tip a few times you can notice a pea-like or nutty flavor. The leaves can be quickly stripped from the stem by pulling it between your fingers. Tender tips, leaves, flowers, and small fruits are eaten.

There is another use for katuk in Borneo. By using plenty of fertilizer and irrigation and a bit of shade, they are able to make the tips grow very quickly. The top 5 inches (13 cm) are harvested (there will be only few leaves) and sold to the finest restaurants. I ordered them at the Hilton Hotel in Borneo then watched as they were cooked. The bottom inch was discarded to ensure only tender tips would be prepared and the remaining 4 inches were cut in two. These were then stir fried for perhaps 60 seconds. They can be eaten raw as well. Malaysian Borneo hopes to export these to Japan as "tropical asparagus." (Of course, it is not really asparagus). A delegate at our Agricultural Missions Conference reported that katuk tips are now being grown and marketed in Hawaii.

Katuk is native to the lowland rain forest understory and prefers a hot, humid climate. It will grow in shade or full sun, and it tolerates occasional flooding and acidic soils. Under ideal conditions, it can grow up to 1.5 m per month. However, stem diameter does not grow apace with length and it soon gets so tall that it falls over, earning its description in Edible Leaves of the Tropics as "an awkward plant." In cultivation, it must be regularly trimmed for optimal production of new shoots. Be sure to keep it pruned to between 3-6 feet (1-2 m) high.

Plant about 2-3 feet apart in full sun or partial shade. Because they use shade cloth in Borneo for producing tender tips, I grow it under the eaves on the north end of my house. An additional benefit here is that plenty of water will fall on the plants from the roof even after a light rain and it will get only filtered light. Some people recommend katuk for alley cropping systems with nitrogen-fixing trees. We have had no disease or insect problems at ECHO, although slugs are reportedly a problem among new cuttings or seedlings in some areas. Katuk will produce abundantly throughout the warm months. During the coldest 2-3 months of winter at ECHO, plants may appear a bit sickly, stop growing, and be less tasty until new growth resumes with warm weather.

Katuk is easily propagated by moderately woody cuttings (20-30 cm long, with at least two nodes), though they can be slow to establish. If you visit ECHO on your way to the field, you can pick up some cuttings. During short days, there will be a lot of small blossoms underneath the stem, which can be stripped right along with the leaves and cooked. Our katuk, vegetatively propagated for some time, flowered but did not produce seed until we acquired plants from a different source (when they produced seed immediately); it is possible that separate plants are required for seed production or some varieties are selected for or against seed production. ECHO seedbank intern Jim Richard collected seed in December and allowed it to air dry until it was planted in January. It germinated in about 3 months. Since 1996 was the first year we successfully grew katuk from seed, we cannot guarantee that we will be able to distribute it from our seedbank, but if you are willing to wait you can request seed from ECHO and we will put your name on a waiting list until seeds are ready in January.

According to Cory Thede in Brazil, "Katuk and false roselle (Hibiscus acetosella) are easy to start from cuttings of any part of the plant, old or new growth (even in the dry season). Strip off most leaves and put the cutting directly into the ground under partial shade. They are survivors and palatable to most people. The false roselle was especially popular because of the red-purple color and sour, tangy flavor. Katuk is a light producer of greens compared to others I grew." [ECHO also has seed of false roselle.]

From ECHO Development Notes, January 2006, Issue 90

FROM ECHO'S SEED BANK

Sauropus androgynus (Katuk): A Nutritious Perennial Green

By Tom Gill, ECHO Seed Bank Assistant Manager

Other common names: Sweet Leaf Bush, Star-Gooseberry, Chekkurmenis, Chekup Manis, Changkok Manis, Japanese Malungay)

Arguably, as we work toward food security the promotion of perennial crops should be at the forefront of our minds. Through their use, we can hope to achieve more constant, year-round production. One of our favorite perennial vegetables for hot, humid climates is Sauropus androgynus, often known as "katuk." Katuk offers high vigor, long life, and year-round production of nutritious greens.

S. androgynus has its origins in the hot, humid lowland rainforest of Borneo. It is more vigorous at lower altitudes but is grown in Malaysia and Indonesia at altitudes of up to 1300 m (4000 ft). Katuk can tolerate occasional flooding and will grow under very wet conditions, where annual rainfall reaches 3000 mm (120 inches). It also tolerates acidic soils. It will grow in full sun or partial shade. Ideal spacing between plants is 60-90 cm (2-3 ft). Because it is native to the rainforest, katuk is an ideal understory species in agroforestry systems.

S. androgynus has a variety of common names, mainly from southeast Asia, where it is grown as a staple vegetable. The tender shoots, flowers, and young and old leaves are all used for food. The leaves are sweet with a nutty flavor, and are reported to have medicinal value-prepared as a vegetable, the leaves are recommended for women after childbirth to stimulate milk production and recovery of the womb (Ram, 1994). Katuk leaves also retain their color and firmness when cooked.

Figure 3: Katuk leaves and flowers. Photo by ECHO staff.

The nutritional value of katuk is exceptional (see Table 3). The leaves contain 6-10% protein by (fresh) weight. It has huge potential for areas of the tropics where vitamin A deficiency is a problem, especially among malnourished children. It has even been reported (Seibert, 1986) that katuk was the major source of food (along with shell fish!) for a few Japanese soldiers who were hiding in Philippine caves for 25 years after World War II!

Table 3: Nutritional value of Sauropus androgynus versus Spinacia oleracea. Serving size 1/2 cup of fresh leaves (Oomen & Grubben, 1978, www.nal.usda.gov/fnic/foodcomp/search/)

	Actual quantity per half cup serving of fresh leaves		% Daily Value USDA, 2000 calorie diet
	Katuk	Spinach	Katuk	Spinach
Protein	4.9 g	0.43 g	9.8	0.9
Calcium	51 mg	15 mg	5.1	1.5
Iron	2.7 mg	0.4 mg	15	2.3
Vitamin A	1122 IU	1407 IU	22	27.6
Vitamin C	83 mg	4.2 mg	138	7

The young shoots of katuk are tender and succulent, and are often prepared as a delicacy in East Asian cuisine. These prized shoots are produced rapidly by farmers in Malaysia, who force new growth of stem tips through appropriate pruning, fertilization, irrigation, and use of shade cloth. Dr. Martin Price, ECHO's Executive Director, comments on these stem tips: "The top 5 inches (13 cm) are harvested...and sold to the finest restaurants. I ordered them at the Hilton Hotel in Borneo then watched as they were stir fried for about one minute. The bottom inch was discarded to ensure only tender tips would be prepared..." (Meitzner & Price, 1996).

Pruning is essential for effective cultivation because, if left unchecked, the plant will grow so tall that it will fall over. Katuk should be pruned to between 1 and 2 meters (3-7 ft). Pruning encourages the constant production of new tender growth. [Ed (MLP): I grow katuk on the north side of our home, in about a three-foot (one meter) area along the wall and under the roof's two-foot overhang. This small area has produced a continual supply of greens (far more than my wife and I can consume) without insect or disease problems for 17 years. Each year it grows so tall it reaches the roof at about 10 feet and is then pruned. Production ceases during the three months each year with coolest temperatures and shortest days.]

S. androgynus may be eaten raw or cooked. However, when raw katuk extract became a popular ingredient of a weight control program in Taiwan in 1994/5, it resulted in several reported cases of poisoning. Those affected were consuming very high quantities of the raw katuk extract with fruit juice, and some developed a rapidly progressive obstructive lung disease, possibly linked with the alkaloid papaverine found in katuk (Ger et al., 1997). It must be stressed, however, that there is no evidence that eating cooked katuk or raw katuk in moderate amounts is harmful in any way.

Katuk flowers are small and red, and are characteristic of the family Euphorbiaceae (see Figure 3). The fruits are pink/yellowish-white round capsules that typically contain 4-6 seeds. The seeds are black when mature. The flowers may be cooked and eaten. One member of our network has even mentioned that he has eaten the fruits, but we are reluctant to recommend that without further information.

Katuk can be propagated by seeds and cuttings. However, the viability of both seeds and cuttings is short-lived, so both should be planted as soon as possible after collection. Seeds are viable for only 3-4 months when kept dry and cool. Even while seeds are still viable, germination will be probably 50% at best. Seeds should be removed just as the seedpod is beginning to crack open. Germination will be higher if the seed coats are pulled off just prior to planting. Seeds should germinate in 2-4 weeks, but they may take up to 5 months. We grow katuk as edible hedges around the ECHO farm. We have noticed that some seeds that have fallen around these hedges have sprouted on their own.

Propagating by cuttings is often preferred to planting seeds. Using an established plant, propagation by cuttings is very easy and highly successful. To propagate, cut a 20-30 cm (8-12 inch) section from a mature branch with 2-3 nodes. Remove all stems and leaves from the cutting, and make sure that the bottom end of the cutting is within 3 cm (1 inch) of a node. Plant the cutting at a depth of 10-15 cm (4-6 inches) with only 1 node exposed. A crop can be harvested just 4 months after planting.

Katuk has minimal pest and disease problems. Minor pests include the Chinese rose beetle (Adoretus sinicus) and slugs, which both can damage young plants.

Although katuk is moderately drought tolerant, it is not an appropriate choice for areas with an extended dry season of 7-8 months, unless there is access to irrigation and/or heavy mulching is practiced. Katuk will also not grow as vigorously in areas with poor or depleted soils, unless considerable quantities of organic matter or other nutrients are applied.

Seeds and/or cuttings are available from ECHO's Seed Bank. Trial-sized packets of seed or cuttings are available free to those working overseas in agricultural development. All others may purchase the seeds or cuttings from ECHO. The overseas price for seeds is $3.50/packet and the domestic price is $3/packet. Cuttings are available for purchase at $5 per cutting, with a minimum order of five cuttings. To place an order, contact us at echo@echonet.org or go to www.echotech.org.

References

Ger, L.P., A.A. Chiang, R.S. Lai, S.M. Chen & C.J. Tseng (1997). Association of Sauropus androgynus and bronchiolitis obliterans syndrome: a hospital-based case-control study. American Journal of Epidemiology 145: 842-849

Meitzner, L. S. & M. L. Price (1996). Amaranth to Zai Holes: Ideas for Growing Food Under Difficult Conditions ECHO, North Fort Myers, Florida.

Oomen, H. A. P. C. & G. J. H. Grubben (1978). Tropical Leaf Vegetables in Human Nutrition. Communication 69, Department of Agriculture Research, Royal Tropical Institute, Amsterdam.

Ram, J. (1994). Sweetleaf Bush. Tropical Vegetable Leaflet No. 10, August 1994. Pacific Islands Farm Manual.

Seibert, R. J. (1986). Tropical Edible Plants for South Florida Coastal Areas. Marie Selby Botanical Gardens.