The hardy kiwi is a wine part of the Actinidiaceae family, which gets its popular name from the fruit that resembles a small kiwi. It is a perennial vine native to Asia, where it grows in Korea, Japan, China and Siberia.
The vine is popularly known as the tara vine or the hardy kiwi, and has the scientific name Actinidia arguta. It is a twinning vine with a woody stem and a fast rate of growth. The hardy kiwi is a deciduous species, valuable for its edible fruit and attractive look. It can be found in the wild in Japan, China and other Eastern Asian countries, where it inhabits forests, swamps and streamside. Hardy kiwi is known for the vigorous growth, it commonly reaches heights of 25-30' but can even climb to 100' if large trees are available for support.
Its leaves have a vivid green color, between 3 and 5" long, with an elliptic or ovate shape. The flowers bloom in June and are about 3/4" long, with a white or green color and an attractive scent. The hardy kiwi fruits are very small, similar in size to grapes, have smooth skin and become ripe in the autumn, from September to October. The flowers are either male or female, which makes it a dioecious species. Female vines will not produce fruits without being pollinated by at least one male plant. The taste is very similar to the one of related Actinidia deliciosa, or the true kiwi, but a bit sweeter.
The plant grows in a radial pattern, resembling the spikes of a wheel. This is why the scientific name of the genus comes from the Greek word aktis, which means ray.
Hardy kiwis have various colors. The smooth skin can be brown, green or almost red. Since the fruit is so small, it can be consumed whole without removing the peel. The peel is thin with a texture resembling leather, while the flesh is tasty and sweet.
Many serious diseases are caused by free radicals, which react with molecules and mutate cells. This is considered to be one of the main causes of cancer, diabetes, cardiovascular diseases and other chronic conditions. Including many vegetables and fruits in your diet is known to severely reduce the risks.
While the human body produces its own antioxidant agents, these are usually not enough and we must supply more such compounds from our daily diet. Fruits and vegetables are very rich in antioxidants, which explain why they provide protection against these diseases.
Modern medicine focuses on a healthy diet as a way to prevent illness. A diet based on whole foods is a lot healthier than one that includes processed products. Fruits and vegetables are a major source of antioxidants. Some of these, like carotenoids, flavonoids or vitamins C and E are well known for their effects. In addition, fruits provide many other bioactive compounds, which have not been properly studied yet. The hardy kiwifruit is very rich in phytochemicals and supplies a sizeable dose of ascorbic acid (vitamin C). Scientists believe that the hardy kiwi fruit might be very valuable in medicine and it has been included in some studies on heart diseases and cancer.
The small hardy kiwifruits are packed with vitamin C and a serving of 100 g supplies about 85 mg of vitamin C. As a result, including hardy kiwi fruits in your diet has important antioxidant effects. Studies have revealed that consuming hardy kiwifruits triggers a number of mechanisms inside the body; it protects lymphocyte DNA from oxidation in vitro, boosts the capacity of lymphocytes to repair DNA damage caused by oxidation, inhibits platelet aggregation, and reduces endogenous oxidation of lymphocyte DNA. Actinidia chinensis, a new variety of kiwifruit with a golden color, has a 20% higher vitamin C content. This makes it even healthier than the normal green type.
Kiwifruits in general are native to the eastern parts of the Asian continent. All members of the Actinidiaceae family have been used for a very long time as both food and medicine. Since ancient times, they were consumed as a treatment for several types of cancer, in particular digestive and mammary ones. The most famous species of the genus is Actinidia deliciosa, or the green kiwi fruit. However, the hardy kiwi (Actinidia arguta) and the gold kiwi (Actinidia Chinensis) have become more and more popular and they are increasingly cultivated. The green kiwi fruit is very well known for its laxative effect. It has been used against constipation for a very long time and recent studies have validated the strong laxative properties of the fruit.
Including hardy kiwi fruits in your diet also counters the symptoms of the irritable bowel syndrome (IBS). This is a very common digestive issue that causes a range of problems. Patients who suffer from IBS alternate between diarrhea and constipation and often report stomach pain.
The hardy kiwi fruit is very rich in serotonin and provides twice the amount found in tomatoes. It is also a major source of carotenoids, flavonoids, anthocyanins, vitamins C, E and other antioxidants. Serotonin is associated with rapid eye movement sleep (REM), being the final step of L-tryptophan metabolism. Insomnia seems to be caused by low levels of this chemical. The hardy kiwi fruit also provides a good amount of folate, another compound needed for normal sleep and other neuropsychiatric processes. People who can't sleep well should include hardy kiwi fruits in their diet, since it helps fighting insomnia.
The hardy kiwi fruit has only been studied as a whole so far. However, it is a natural source for many small peptides that haven't been properly researched. Some of these chemicals might have strong bioactive properties and deserve more attention from scientists. One of these small peptides found in the hardy kiwi fruit is kissper. It is synthetized by proteolytic cleavage from kiwellin, which is a protein included in large amounts in the fruit. Kissper has a very resilient molecule, which makes it invulnerable to gastric acid and might allow it to pass the human digestive system. As a result, some researchers suspect that it could have a direct influence on the digestive function. One particular study that focused on this aspect found that hardy kiwi fruit peptide provides benefits to the human gastrointestinal physiology. Kissper might also provide a strong anti-inflammatory effect at the level of the gastrointestinal tract and influence the local physiological and pathological conditions. It is considered a possible ingredient in drugs used to treat inflammation of the intestines.
Because of the high amount of vitamins and phytochemicals, hardy kiwis are a natural protective food. One study has showed that cells exposed to hydrogen peroxide managed to survive after being protected by the hardy kiwi fruit extract. The powerful antioxidant effect shield tissues and cells from the destruction caused by free radicals and the stress of insomnia and poor diets.
The hardy kiwi fruit is very rich in vitamin C, which is known to increase the absorption of iron. It is a natural pair for foods with high iron content, which is very helpful for people who suffer from anemia or other forms of iron deficiency.
Like many other fruits, kiwis are a great source of dietary fibers. Fibers are critical for proper digestion and consuming the fruit can counter the symptoms of IBD, such as diarrhea, constipation and abdominal pain. According to a study on IBD patients published in 2010, two kiwis per day improved bowel function as well as colon transit time and frequency of defecation. Kiwis also boost the effectiveness of the immune system and can prevent common cold, which is especially useful for kids and elders who are more vulnerable to infections.
Nutritionists are quite enthusiastic about hardy kiwis and include them on the list of the healthiest natural foods, due to their health benefits. They provide a powerful package of carotenoids, potassium, fiber, phytochemicals, vitamins C, E, K, and folate. Eating them prevents high blood pressure, the formation of blood clots, increases the level of HDL cholesterol and decrease the amount of triglycerides in the blood.
The plant is named the hardy kiwi due to the very fast rate of growth. It climbs to the top of high trees and can survive temperatures as low as -30 °F. However, spring frost can damage immature shoots. Hardy kiwi tolerates winter frost and actually requires it in cultivation. The plant needs around 150 days without frost per year and adapt to temperature changes as long as they are gradual. Very sudden periods of frost will kill young plants and split established vines. For proper cultivation, at least some winter chill is required.
Seeds are viable and the time needed for germination is about one month. However, cuttings are another popular way to propagate the hardy kiwi vines. Cuttings of hardy kiwi can grow on their own roots but it is also possible to graft them on existing rootstock.
In order to allow horizontal growth and simplify harvesting and routine works, a trellis is often used in cultivation. A trellis with strong structure is needed, since the plants grow and climb vigorously. In good conditions, every vine is able to grow up to 20 ft per season. It is also important to consider positioning in commercial plantations. Hardy kiwi needs full sunlight in order to produce the best yields, even if some shade is tolerated as well. The hardy kiwi vines absorb large amounts of water, so in order to prevent root rot they are planted in acidic soils with good drainage.