(NZ Herald)- Whether for ecological or commercial reasons, organic and sustainable winegrowing is taking off.Wine is now available in three colours: red, white and increasingly in fashionable shades of green as New Zealand's vineyards undergo a natural revolution. Not only are the majority of our winegrowers now signed up to the country's sustainable winegrowing scheme, but 20 per cent of our vineyards could be organic within a decade if a recently set target is hit.