Many cultures in Hawaiʻi have their own names for sweet potato. Kamote is the Tagalog name, and in Aotearoa (New Zealand) they are widely farmed and are called kumara.
In Hawaiʻi, ʻuala is also called ʻuwala. The ʻuala is the second in importance to kalo (taro) as a staple starch food in old Hawaiʻi.
He ʻuala ka ʻai hoʻola koke i ka wi.
The sweet potato is the food that ends famine quickly
(ʻŌlelo Noʻeau from Pukui)
It is in the Morning Glory family and grows easy and it grows fast – within 4-5 months of planting (as opposed to nine to eighteen months for taro), ʻuala is cultivated for their enlarged primary roots called “tubers” (the primary food from the ʻuala,) while leaves can also be eaten.
Tubers were also used as bait for fishing; Vines were used to make an under cushion for lauhala mats in houses; and Fermented ʻuala “beer” (ʻuala ʻawaʻawa) brewed, but it is unclear if this is a pre-contact practice. (Bishop Museum)
ʻUala, sweet potato, was a canoe crop (it was brought to Hawaiʻi by the Polynesians, who brought with them shoots, roots, cuttings and seeds of various plants for food, cordage, medicine, fabric, containers, all of life’s vital needs.)
It is known as the 2nd staple for the Hawaiians. It is said to have been cultivated in Hawaiʻi since about AD 1000. The tubers are consumed after cooking primarily in an imu. Other plant parts were used as animal feed. (UH-KCC)
It’s been called a super food – the average sweet potato weighs 6.5 ounces (about 3/4 cup) and contains 180 calories. It supplies 14 percent of your daily carbohydrate requirement (good carbs) and 26 percent of your daily fiber needs. It is an excellent source of vitamins A and C, potassium, calcium and folate. (Miyasaka)
Purple-fleshed or orange-fleshed varieties are rich in beta carotene and have more anti-oxidants than blueberries. In addition, all sweet potatoes have a low glycemic index. This index is a measure of how quickly foods are broken down into sugars in the human body and converted to body fat. (Miyasaka)
The sweet potato plant grows in dry places. You can find it in low and high areas up to 5,000 feet in elevation. It can also be found in damp valleys although it doesn’t need a lot of water like taro does.
Farming of ʻuala on a large scale was involved the systematic cultivation of dryland crops in their appropriate vegetation zones as exemplified by the Field Systems in Kona, Kohala, Kaupō and Kalaupapa (Kaʻū reportedly also has a field system.)
Cultivation of the soil “was generally divided into small fields, about fifteen rods square fenced with low stone walls, built with fragments of lava gathered from the surface of the enclosures. These fields were planted with bananas, sweet potatoes, mountain taro, paper mulberry plants, melons, and sugar-cane, which flourished luxuriantly in every direction.” (Reverend William Ellis)
Farmers found, farmed and intensified production on lands that were between being too wet and too dry. Archaeological evidence of intensive cultivation of sweet potato and other dryland crops is extensive, including walls, terraces, mounds and other features.
In Kona, the field system was quite large, extending from Kailua to south of Honaunau. In lower elevations all the way to the shore, informal clearings, mounds and terraces were used to plant sweet potatoes; and on the forest fringe above the walled fields there were clearings, mounds and terraces. Sweet potatoes grew among the breadfruit.
In Kohala, the fields were oriented parallel to the elevation contours and the walls (and perhaps kō (sugar cane) planted on them) would have functioned as windbreaks from the trade winds which sweep down the slopes of the Kohala mountains.
Configured in this way, the walls would also have reduced evapotranspiration and – with heavy mulching – retained essential moisture for the crops. This alignment of fields also conserved water by retaining and dispersing surface run-off and inhibited wind erosion and soil creep.
Based on experimental plantings, if only half of the Kohala Field System was in production in one year, it could be producing between 20,000 to 120,000-tons of sweet potato in one crop.
At Kaupō, on the slopes of Haleakalā, the field system is associated in Hawaiian oral traditions with Kekaulike, a famous Maui king (ali‘i nui) who on genealogical estimates is dated to approximately the early eighteenth century.
Kekaulike made Kaupō his residential seat, and assembled his army at Mokulau, preparing for a war of conquest against his rivals on Hawai‘i Island.
Given its use as a Royal Center for Island Ali‘i, there was a definite need for sufficient crop production. Fortunately, the area has an ideal combination of soils, elevation and rainfall making it also a predictable environment for an intensive dryland field system to feed the people.
Historic records note that this region was identified as “the greatest continuous dry planting area in the Hawaiian islands,” both in ancient times and well into the 1930s.
The field system a closely spaced grid of east-west embankments and small field plots bisected at right angles by longer north-south trending walls; it covered an area of 3,000 to nearly 4,000-acres and could have supported a population of 8,000-10,000 people.
At Kalaupapa peninsula, archaeological and carbon-dating evidence indicate that the initial settlement and presence of people on the Kalaupapa (“the flat plain”) peninsula on the Island of Molokaʻi was between 800 and 1200.
There is a grid of rain-fed plots, defined by low stone field walls built, in part, to shelter sweet potatoes and other crops from trade winds, that cover the Kalaupapa Peninsula. It appears that the field system was a secondary area of settlement and agricultural development, with the wetter valley and sediment soil being the preferred areas.
Instead of enclosed fields associated with the more recent historic era, archaeologists found dense rows of unenclosed alignments and substantial house sites quite unlike the temporary shelters found in other Hawaiian field systems.
At Kōloa, Kauaʻi, another unique feature was found; the early Hawaiians constructed sophisticated irrigation systems tapping off of Waikomo Stream for growing their crops.
Beginning possibly as early as 1450, the Kōloa Field System was planned and built on the shallow lava soils to the east and west of Waikomo Stream. It is characterized as a network of fields of both irrigated and dryland crops, built mainly upon one stream system. Waikomo Stream was adapted into an inverted tree model with smaller branches leading off larger branches.
This agricultural system which at its peak covered over 1,000 acres extends from the present Kōloa town to the shoreline and includes a complex of wet and dryland agricultural fields and associated habitation sites.
Commercial sweet potato cultivation in the islands began in 1849. In 1919, sweet potato was considered tenth in value among agricultural crops in Hawai’i when grown as an emergency crop during the war years. (Lots of information from Vitousek, Kirch, McCoy and Hammatt)
The image shows ʻuala greens and blossoms; in addition, I have added some other images in a folder of like name in the Photos section on my Facebook and Google+ pages.