You’ll see the same on any vineyard across the planet, whether it’s in La Mancha, France or in New World countries like New Zealand and the United States. Although this may seem like a merely decorative touch or the sign of a resident rose-growing enthusiast, the presence of rose bushes in vineyards has nothing to do with either appearance or hobbies. They are there for organic, biological reasons, for a purely preventive purpose. Rose bushes, as plants, work as indicators of the appearance of some kind of fungal anomaly in the vineyard.
One of the most dreaded diseases is powdery mildew. This parasitic fungus forms on the vine leaves and is very difficult to combat if not detected in time. Some flowers like roses are also sensitive to this kind of attack, showing identical symptoms such as stains on the leaves formed by a network of whitish, powdery strands.
This is why rose bushes are planted at the end of every row of vines, as an alarm system. If they are affected, there’s time to stop the disease in its tracks. It’s a natural, environmentally friendly technique that’s highly effective, especially in organic wine production.
Appearance of powdery mildew on vine leaves. Source: VitiViniCultura.net
Some people think the tradition dates back to the mid-19th century (when the health of European vines was severely threatened by diseases like phylloxera). It was in 1851 when French vineyards were apparently decimated by the arrival of Oídium tuckeri mould spores from Great Britain.
Up to that time, French vine cultivation was limited to land around monasteries. It was actually on land belonging to Cîteaux Abbey (in what is now the Burgundy region) where they came up with the solution. There, in previous centuries, the Cistercian monks had been innovators in wine production, exporting their techniques to the rest of the Medieval Christian world. Experimental monitoring of the vines led them to notice that roses behaved in a similar way to vines when affected by mould. They then found that aerating the foliage by pruning the still young leaves or treating more advanced cases with sulphur seemed to be successful. This is why rose bushes are extremely useful and decorative allies in vineyards and other plantations.
However, it’s also important to add that plants in areas with excessive shade and too much moisture are extremely vulnerable to mould. The right amount of exposure to sunshine keeps the risk to a minimum.
And of course, sunshine is something La Mancha has in abundance!