My Green Wet Thumb: The Enduring Taro

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Wilfrid McBride
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1 My Green Wet Thumb: The Enduring Taro Derek P.S. Tustin My pond planning planting was almost done for the year, and soon the maintenance and enjoyment would begin. I m sure most of you are familiar with that point you come to in any project, be it the adding of fish to a tank, the planting of a pond or aquarium, or the construction or installation of a piece of equipment or décor, where you just sit back and look, enjoying what it is you have accomplished. Now I don t know about you, but I love that point because it is the accomplishment of something, but I also loathe it, because it means I think about what I have done, and what I have to do next. But before I could get to that point (remember I said my pond planting was almost done?) I had one last hole to fill. This past weekend I went to a nursery located near where I lived with the specific goal of buying a new Taro plant for my tub garden. I actually picked up two, Taro Black Magic and the Imperial Taro, and planted them over the weekend. After I was finished I was sitting with my wife looking at it and she innocently asked Are they the same species? and I had to answer that I didn t know. So doing what I do when I don t know, I set out to find out more and was shocked at what I didn t know The Distinguished History of Taro I live in what is known as the Greater Toronto Area, or the GTA. Consisting of Toronto proper and the surrounding suburbs, it is deemed to be the 51 st largest metropolitan area in the world, and home to an estimated 6,139,000 people. If you stop and think about it, the number is staggering. But 10,000 years ago, the population of the entire planet was estimated to be less than 5,000,000. Image, fewer people on the entire planet than live within an hour s drive of my home 10,000 years ago the earth was emerging from the last the ice age, and some hunter-gather civilizations were changing to agricultural based. One of the first crops to be cultivated was Colocasia esculenta, what we today call the Taro plant. Paleoethnobotanists, that is archaeologists who study plants found at archaeological sites, have determined that Colocasia esculenta was first cultivated in swampy regions of tropical and subtropical Asia. The Taro plant, 6 The Tropical News

2 while known to gardeners and pond enthusiasts today, was at that time considered to be an important plant to the emerging cultures. It is actually a perennial herb wherein almost every part of the plant can be consumed. The tuber (often incorrectly identified as a corm or bulb) can be baked, boiled or steamed, and the leaves and stems can also be eaten after being cooked. (Actually, when discussing the Taro as a food source, the most important fact that must be known is that any portion of the plant which is to be consumed must be cooked. Every portion of the Taro contains calcium oxalate crystals. Calcium oxalate is a chemical compound found in over 1,000 genera of plants, and whose function is to detoxify surplus calcium being absorbed by the plant. Calcium oxalate crystals, also known as raphides, form as the plant processes the surplus calcium, and they take the form of small needle shaped crystals that are indiscernible to the human eye. It is believed that these crystals are a defense mechanism on the part of the plant to prevent predation by herbivores. When ingested, they cause a burning and / or stinging sensitive to the throat and mouth lining. Luckily, the irritation caused by consuming raw Taro is relatively minor, but is removed completely by cooking the parts of the plant to be consumed.) As humanity spread across the planet, they carried the Taro plant with them (Continued on page 12) The Sacramento Aquarium Society 7

(Continued from page 7) for cultivation purposes, and it was through this dispersion of humanity that Taro came to be found across the world, including Southeast Asia, the Caribbean, South and

3 (Continued from page 7) for cultivation purposes, and it was through this dispersion of humanity that Taro came to be found across the world, including Southeast Asia, the Caribbean, South and Central America, Polynesia and, through Polynesia settlers, Hawaii. Between 300 and 800 CE it is believed that Polynesians travelled to and settled Hawaii, bringing with them their language, culture and the Taro plant. While used to great benefit in the other locales where the plant has become established, it is in Hawaii where greatest utilization of all aspects of the plant has been realized. The climate of Hawaii is well suited to the cultivation of the Taro plant, and the plant was soon flourishing across the islands. In was inter-cropped with other species of cultivated vegetation, including bananas, papayas, coconuts and green peas, and flourished with the care that it was given. Given the benefits that their culture received from their usage of the Taro, which the Hawaiians call Kalo, it is understandable why it came to be considered a sacred plant in their culture, featuring as part of the Hawaiian creation story. In addition to the aforementioned methods of preparation for cooking, the Hawaiians found numerous other ways to prepare it. The immature leaves of the plant can be cooked in water or steamed and served as greens, are sometimes cooked with coconut milk, and at other times served in a leaf packet. The stems are peeled and boiled for consumption, and the tuber is sometimes grated and steamed or baked with coconut cream to make 12 The Tropical News

4 kulolo, a pudding like desert. Other cultures around the world use the Taro plant as part of their diet in a variety of dishes. In fact, one of the common names of the plant is Potato of the Tropics because it is a food source in many varied tropical cultures. But the recognition of the nutritional benefits of the Taro plant has grown far beyond only tropical cultures. It is estimated that Taro is the fourteenth most -consumed vegetable in the world, and it has been reported that on some Soviet-era space flights, dehydrated Taro was included as a part of the food supply. But the enduring legacy of the Taro plant to cuisine is that it is the basis for the Hawaiian food called poi. Poi is made by taking a cooked Taro tuber (either baked or steamed) and mashing it until is a viscous fluid. Water is added just before eating to achieve a consistency ranging from liquid to a doughy consistency. The variation is the consistency is measured as one, two or three-fingered, which refers to the number of fingers needed to eat it depending on the consistency. Poi is actually a very versatile food with a wide range of benefits. It can be used as a milk substitute for babies born with an allergy to dairy products, and further is used as a baby food for children with severe food allergies. It is hypoallergenic, and is one of the easiest foods to digest, often being used by the elderly. But as with all different types of foods, different varieties give differing results. Over the centuries, Hawaiian famers began to selectively propagate different varieties of the plant to achieve different and desired outcomes. Some of the plants had more tender leaves, some were more suitable for poi, and others demonstrated heightened medicinal properties. The first European contact with the Hawaiian Islands was made by the British explorer James Cook in When he arrived, there were in excess of 300 different varieties of Taro under cultivation in Hawaii. Today, with the decline in the inter-cropping of the Taro plant with other species of plants and the increase in monoculture (growing only a single crop of one species of plant at one location, rather that growing several species of plants intermingled), there has been an increase in disease and parasitic species (most notably Pomacea or Apple Snail species) adversely affecting the Taro plants. As a result, it is estimated that there are only 12 different varieties of Taro now being cultivated in Hawaii. (Continued on page 15) The Sacramento Aquarium Society 13

5 Different Faces While the history of the Taro in relation to the development of human civilization is interesting, looking at it from a botanical aspect is just as fascinating. As has been shown, the plant has been known to various civilizations from across the globe for more than 10,000 years. But it wasn t until the advent and rise of the classification systems created by Europeans that the Taro plant was given a scientific name. It was first described by Heinrich Wilhelm Schott (an Austrian botanist who worked extensively with aroids) in The genus name is derived from the ancient Greek word kolocasion, which was created by the ancient Greek botanist Dioscorides in the 1 st century CE, and referred specifically to the edible roots of both what we now know as Colocasia esculenta and Nelumbo nucifera, or the Indian Lotus. The species name, esculenta, is the Latin word for edible. So literally, edible roots that are edible! (It is interesting to note that many sources actually record the scientific name of the Taro plant as Colocasia esculentum. In actually fact, Colocasia esculentum is not the proper name, likely being the result of someone mixing up the name of another plant, Caladium esculentum, with that of the Colocasia esculenta.) As mentioned, there were about 300 different varieties of this plant known to have been existed in Hawaii alone, and this excludes the different varieties grown in other locations around the globe. Today, there are about 200 different known varieties, and the appearance of these different varieties can be striking. They range in extreme differences in height, leaf size, leaf shape, leaf colouration, stalk colouration and tuber size and shape. But while these different varieties do exist, they are in fact all the same species, Colocasia esculenta. The different appearances have lead many botanists who find a variety of Taro that looks significantly different to assume they have discovered a new species. As a result, there are in excess of 70 synonym scientific names, and you will often find the plant for sale under one of those incorrect names. For a plant that has been part of human history for 10,000 years, and for a plant that is so important to the diet of so many cultures, very little is actually known about the plant. Description and Care The plant itself features large arrow-shaped (sagittate) leaves growing from erect stems, which in turn have grown from the tuber beneath the surface. The tuber, edible as mentioned earlier, is where the plant stores starch which has been produced by the leaves, and can vary in size and colouration. Both the stalks (which can reach 60 or 5 [150 cm] in height) and the leaves can vary in appearance from light green to dark green to red / burgundy to black and may be variegated. The large arrow-shaped leaves are the source of the common name for Colocasia esculenta, Elephant Ears. The Sacramento Aquarium Society 15

6 While descriptive of the leaves of the Taro, the name is also somewhat inaccurate as Elephant Ears can be used to describe the appearance of several other species of plant that also have similar shaped leaves, such as plants from the Alocasia genus. The leaves and stems emerge from the innermost stalk, unfurling as they grow. Propagation can either be through flowering or through additional tubers and / or stolons (long runners) being sent off from the base of the plant. Sexual reproduction through flowering, while the main method of propagation in cultivation, is only rarely realized in a pond environment. The plant will produce a flower stalk at the top of a spathe, which appears as a yellow or white tube shaped structure. Inside the spathe grows a spadix, an erect spike which houses both the male flowers (near the top and producing pollen) and female flowers (near the base and being receptive to pollen). However, the male flowers do not produce pollen when the female flowers are receptive, and vice versa. Therefore, two different plants, both in flower at the same time but with the male flower of one plant producing pollen and the female flower of the other plant being receptive to pollen, are required. Further hindering sexual reproduction is that a method of transferring the pollen from one plant to the other is required. In nature, this role is usually undertaken by insects, but it can be artificially accomplished if the above noted status of the respective plants is realized. (It should also be noted that the appearance and size of both the spathe and spadix are, like all other aspects of the Taro, extremely variable from plant to plant.) While Colocasia esculenta can be grown as a terrestrial plant (given sufficient water) and will reach maturity quicker when grown in that fashion, it is best grown as an emersed plant. The stalk of the plant is actually filled with air spaces, and this permits underwater gaseous exchange with the atmosphere. In order to realize the maximum supply of dissolved oxygen, the water should be cool and flowing as stagnant or standing warm water will result in rotting of the tuber and base of the plant. As is indicated by the countries and locations around the world where the plant is now found, it prefers warm environs. Best growth is realized at temperatures between 68 and 86 o F (20 to 30 o C), and will likely be damaged if temperatures fall below 50 o F (10 o C) for more than a few days. That being said, it is relatively hardy, and reportedly will continue to grown after a light snowfall or frost if temperatures rebound in a short period of time. In areas where winter is not severe, it can be left in the ground over the winter, and in areas where winter is severe, can be overwintered indoors (although in my experience will suffer a significant die back). In nature, the Taro will often be found growing along the edges of streams and ponds. When used as a pond ornamental plant, it is recommended that it be planted in a larger container with a slightly acidic moisture-retentive soil. The base of the plant should always be kept submerged, and the plant itself 16 The Tropical News

7 exposed to moving water. As with most emersed plants, soil fertilization through root tabs is highly recommended, and will result in better growth. Placement in direct sunlight is preferable, with Taros being planted in the shade tending to grow towards areas of full sun exposure, and often growing taller in order to do so than specimens planted in direct sunlight, which may remain more compact. With its affinity for warm locations and flowing water, care must be taken in geographic locations featuring the preferred growth conditions that the plant not become invasive. While it can be argued that this is one of the earliest known examples of an invasive plant (if we take the position that an invasive species is one outside of its natural range and present due to actions of humans), several states, most notably Texas, Louisiana and Florida, have experienced colonies of Colocasia esculenta that have out-competed native flora in several locations. So now I ve done my research and I think my wife regrets her innocent query if my two Taros were the same species because all that I ve shared with you, I ve told her as well. You may well share my interest in the fascinating history of this common pond plant (and I hope you do), but I don t think my wife did, because at the end of my explanation her response was Oh well, I just like how they look! Colocasia esculenta Latin Name: Colocasia esculenta Common Names: Taro Elephant Ear Kalo Callaloo Dasheen Eddy Root Potato of the Tropics Height: 60 / 5 (150 cm) Planting Depth: 6 (15 cm) Light: Full sun to part shade Temperature: o C (68 86 o F) Growth: Fast Difficulty: Easy Origins: Originally Southeast Asia Now Cosmopolitan Images: The Sacramento Aquarium Society 17

My Green Wet Thumb: Lagenandra

My Green Wet Thumb: Lagenandra By Derek P.S. Tustin Over the years I have found that the average aquarist will go through several different stages. I am by no means a sociologist specializing in the aquarium