Santorini is one of the most surreal vine growing environments on the planet. The island sits on an active volcano, with extremely young and infertile soils, with almost zero potassium and almost zero clay. This last characteristic makes Santorini not just Phylloxera-free but Phylloxera-immune, meaning that the Phylloxera bug will never have the chance to invade the island.
The climate of the island is hot Mediterranean, with very little rainfall during the growing season but plenty of sunlight and fierce winds. Without fog coming out of the caldera every morning, providing moisture in a most sophisticated drip irrigation system provided by nature, very little vegetation could survive in Santorini.
The "basket" prunning
The kouloura, basket shaped, training system of Santorini was developed, out of millennia of trial and error, as a response or even consequence of this bizarre growing environment. The compact shape of the basket protects inside it the flowers and later the fruit from the severe winds, while it also traps humidity. The downside of it is low, very low yields.
When the above ground part of the vine, the basket, gets too big and too hard to work with, it is removed, while a cane close to the root system, undisturbed by Phylloxera, is kept to provide growth for the new basket. Therefore, the age of the above-ground part of the vines in Santorini is usually different from that of the root system, which can exceed one or even two centuries. Santorini, for sure, contains some of the oldest vitis vinifera specimens in the world.