Roots around roots
A herbarium (and arboretum) of our vine’s most important subterranean neighbours.
Olive trees and grapevines are frequent bedfellows not just because they enjoy similar climates, for example, but because olive groves, the far hardier of the two, offer a windbreak to vines in high winds. In Roman times, grape vines would grow on top of trees – be it fig, or olive, or nut- for the practical reason of a physical, sky-high trellis, yes. But more than anything, because benefits would abound below ground level.
Firstly: consider the scale.
On a mature vine, the surface area of roots is estimated to be somewhere around 100 m2 – dwarfing the 10 m2 of above-ground leaf area. Hidden out of sight, its range is extraordinary: a vascular system dispatching hydration, hormones, and minerals. A stretched-wide anchor offering safety in a storm. A subterranean safe resource-hoarding and storing sustenance for darker and dryer months, and as we are increasingly understanding, the host of a kaleidoscopic universe of microbiota.
The root microbiome (or microbiota, or rhizosphere microbiome, if taking into account the soil level it mostly occupies) is the community of microorganisms – spanning fungi, bacteria, oomycetes, and archaea – which live in association with plant’s roots. Think of it as a parallel to the human gut microbiome. Even with research about the latter still in its infancy, we already know there are 10 times the number of microbial cells in the human gut than in the whole human body, and that its impact on our health is unquantifiable.
The same is true below ground. Microorganisms help broaden immune functions of the plant host.By releasing compounds in the rhizosphere plants can ‘recruit’ the microorganisms they need, to stimulate health and growth. Part of the plant’s pan-genome, these microorganisms, as we are coming to understand, are a way in which plants communicate and interact with one another.
What this means, is that when you are tending to vines and their myriad, twisting roots underneath, you are also in deep conversation with everything else in the rhizosphere. The scale of the ecosystem is close to unfathomable.
So here’s to the vine stock, burrowing around a meter down with its thick brown-black, knotty main roots, and proliferation of snow-white new shoots, and here’s to its most crucial allies:
Each year, as the colder weather edges closer, estate managers across our vineyards use a decision tree to make a call on cover crops. Sown to grow like a winter blanket, cover crops are not planted to be harvested, but rather to reduce soil erosion, increase the fertility of the soil and offer a palette of supplementary effects. Assessing what the vines need on a plot by plot basis – using eyes, touch and the occasional bird’s-eye view of a small drone – the team takes into account vigour, yield, and plant health to create a prescription. Here’s what the doctor might order:
A king among cover crops, oat grows at champion speed, and is a natural — in every sense of the word — at suppressing weeds. With its tall leaf blades and tiny florets, oat is a heroic fallen soldier too: if they’re ‘winter killed’, they provide insulation for all the life beneath them.
The common vetch, with its delicate, sail-like purple petal and its slightly crescented legume pod, can be cooked and eaten – its carbonised remains were found in neolithic sites across Syria and Turkey. For our vines, however, it stays infinitely cool. Winter hardy, its standout skill is its ‘nitrogen fixing’; see also clover:
Abundantly nitrogen-producing , clover is excellent at offering a helping hand to vines lacking vigour. The major component of chlorophyll, nitrogen, makes up one of the largest compounds in healthy plants, but cannot be drawn directly from the atmosphere. Instead, nitrogen released into the soil – by say, clover – can be converted into usable form by the root system’s hard-at-work microorganisms. Clover has the added benefit of facilitating treasure hunts for extra luck: there are many four-leafs to be found around the Lafite grounds if you look hard enough.
And if the plot is looking a little too vigorous? Fescue to the rescue. A competitive soul, Fescue’s deep, strong roots suck up water and nitrogen, tempering the vine’s supply, where needed.
Cover plot prescriptions might be made up of a single variety, or – best of all – a multivitamin. At Château L’Evangile, for example, our go-to blend is dubbed ‘Les Graines Folles’, or ‘Crazy Seeds’.
Seeds of the Future: Left, what might be mistaken for the wares of a spice-market is actually a photo of our wild seeding process at Château L’Évangile; we scatter ‘classic’ mixtures of grasses and legumes, combining endemic species from the region that are adapted to our climate – such as Calendula, Plantain, and Ornithopus. These plants will impart nutrients back into the soil that are absorbed by our growing vines, and encourage both beneficial insects and diverse wildlife.
One of the recent jig-saw puzzle challenges at Lafite has been how to connect the 200 hectares of marshland on our property to the vineyard, to create a self-contained, natural irrigation system. The answer? Hedges.
Plotting the location of these endemic hedge corridors is a complex art – you have to take into account elevation and orientation over huge areas, and also wind channels, lest you unintentionally trap cold wind above a particular plot. And of course, you need to take into account the turning pinch-points of tractors.
Helping with delineation and irrigation, hedges also make fine homes, with multiple ‘floors’ for habitation. Moss, flowers, insects, small birds and mammals: a beautifully hedged bet on biodiversity.
Teams at the Bordeaux estates have also been using natural companions up and above ground level. An abundance of medicinal herbs and flowers grow in and around our estates. Their second life? As a ‘tisane’, or tea — served, in spray form, to the vines.
“Camomile and yarrow can be balm-like after frost,” Brando says. “And before the frost starts, Valerian, an essence humans consume too, often to assist with sleeping. If mildew appears, oak bark is a natural remedy.“
The method for tea-making? If it’s a cure for a small area, a pan on the stove with water will do, just like the tea you’d make at home, minus any milk or sugar. For larger scale treatments, we have special 400 litre capacity ‘kettles’ where temperature and maceration length can be controlled to exactitude. Over at Evangile, one of the specialty house cocktails is an ‘anti-cryptogamic’ herbal tea – a golden concoction that limits the unwanted intrusion of mushrooms.
At the end of each row of vines at Rieussec is a rose bush. Attractors of pollinators (brilliant for diversity, even if grapevines are self-pollinating), there are also old vignerons’ tales of horses that plowed rows guided by the scent of rose. It’s also said roses, in their delicacy, can operate as an early disease detection system, but as Brando points out, today, Rieussec’s roses are above all aesthetic: good vignerons should know something is wrong with the vine well before the rose shows any visible signs.
At Domaine d’Aussières, tucked away in a circular valley south of coastal Narbonne, Mediterranean herbs grow all around us in the iron-ore rich soil. Their perfume can be intoxicating, particularly in the midday Southern sun. Not only do they ante up with full-service antibacterial, antiviral, anti-fungal, and anti-parasitic qualities, an added bonus with these aromatics is that due to the volatility of some of their molecules, their fresh herbaceous notes can give a little wink to the wine itself. In Los Vascos, too, the same can be said of the tall eucalyptus (Eucalyptus globulus) which presides over some plots: a beautiful cool note hidden in warmth of Carmenere or Cabernet Sauvignon.
In the Qiu Shan Valley, China, beyond Long Dai’s immediate vine-planted terraces, and beyond the fruit and nut trees – cherries, apples, peanuts – that wrap around it, are vast forests of tall pine trees. Our vignerons at Long Dai scatter chips from these local pines to create their winter ‘moquette’, or mulch. Across the estates, mulch trials are all locally adapted, championing elements whose roots are close to home. At Château L’Evangile, this means straw harvested from nearby pastures, and in Los Vascos, the gentle crunch underfoot of Chilean walnut shells.
“If the viticulturist works towards a complexity in its vineyard,” Brando says, “the winemaker will work towards a complexity in their wine. Today we’re working right down at the colloidal level, which is to say with the particles in the wine. We’re understanding more and more how they interact. And you can compare it to a system of roots, in terms of the way the molecules are in conversation. At the end, what this means is more truthful wines: finer aromas that will keep their profile better because of a richer, chewier tannic structure. Very truthful wines is the best way to put it.”