The oval fruits of a plant of Chinese origin, whose botanical name is actinidia deliciosa, or actinidia chinensis, are commonly called kiwis; these plants are widespread in Asia, and in particular in China, where the fruit has been used by man for centuries. In China there are not many cultivations of this type, as the availability of plants in the wild makes human cultivation unnecessary; only in the early 1900s did the cultivation of this fruit for initially decorative purposes begin, by a New Zealand teacher, who picked up the seeds of these plants in China, and brought them home. Since then, the history of kiwis has traveled all over the globe, until it reached Europe, towards the end of the 1900s. Today the country that grows the most kiwis in the world is Italy, followed by New Zealand, France, and Chile and a few other nations. Initially the cultivations in Italy began in Trentino, in areas where traditionally only plums and apples were grown; today there are also crops in Lazio, Friuli and Veneto.
From a botanical point of view, actinidia is a liana, or a climbing shrub, which produces thin stems capable of clinging to any support; in Italy hybrids are grown, derived from actinidia deliciosa, which are bred like vines to form rows. They have thin stems, with dark bark, and large oval or cordiform, deciduous leaves.
The fruits of actinidia deliciosa have brown, hairy skin, with a large content of tannins, which makes it inedible; the pulp is green, dotted with small dark seeds, which attach themselves with filaments to a lighter fleshy part that runs through the center of the fruit. In Asia there are other species, for example actinidia chinensis has yellow flesh, but there are also fruits with orange or pink flesh; for some strange reason the horticultural varieties with fruits with a more usual colored pulp for a fruit, therefore not green, have not had the same success on the European tables; for this reason, in Italy mainly varieties derived from green pulp kiwis are grown.
These plants originate in areas of the world which have a quite different climate from the Mediterranean one; what they need to develop consists of good humidity, and very hot summers.
In fact, to overcome the summer drought, in Italy the kiwis are irrigated during the summer, and in areas with a particularly dry climate, it is preferred to plant the plants in a semi-shaded area, in order to protect them from the scorching sun in the hot summer days. In addition to this, to keep the soil fairly humid and fresh, we tend to mulch it, all year round, in order to keep part of the humidity close to the foot of the plants.
Generally they do not fear frost, even if intense, even if occasional late snowfalls, or very intense frosts, cause the deterioration of the older branches, and can cause fruitless years.