Hidden in this mess of mustard is a head trained vine. I do not know the varietal although I could find out as Vinomaker knows its dad. Just look at it. Brilliant! I love head trained vines. Look at the permanent structure. Cast your eye over the pruning work needing to be done. Fantastic!
The grapevine is...a vine...quelle surprise! It will twist and turn its way up a tree, or anything taller than itself, in order to reach the top and...the sunlight. Truly head trained vines give little support to the actual vine except for their own established trunk. The pruner maintains an almost cartwheel-like structure on which the fruiting spurs are renewed each year. Fabulous!
The main advantage is that it is an extremely cost effective way of training. No stakes, no trellising, and in the case of a dry farmed vineyard, no costly irrigation system. The disadvantages are many. For example, greater instances of disease, heightened pest management issues, and it's bad on your back at harvest time...but like high heels, from adversity comes great pleasure.