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A Technical Guide for Wine Producers
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RECENT ARTICLES | WYNBOER HOME
Practical viticultural experience of certain "new" cultivars:
Viognier, Petit Verdot, Tannat, Mourvédre.
This is the second in a series of four articles about the performance of the above four cultivars under South African conditions. Part 2 is dedicated to Mourvèdre.
PART 2: Mourvèdre
Origin and cultivation
There is little doubt that Mourvèdre originated in Spain. It is probably named after the little town of Murviedro near Valencia or after Mataró, which lies to the north of Barcelona. Mourvèdre has various synonyms and is known as Monastrell in Spain, where more than 100 000 hectares are cultivated. It is also widespread in the south of France in the Lanquedoc-Roussillon area, where it is called Mourvèdre. In Australia and California, where there are considerable plantings, it is referred to as Mataro. In South Africa the official name on the cultivar register was recently changed to Mourvèdre.
The home of Mourvèdre is in Spain, however, where it is the second most planted red cultivar after Grenache. The biggest plantings occur in the eastern coastal regions and central eastern parts of the country. Well-known coastal cities in these regions include Valencia and Alicante, from where the Mourvèdre plantings extend towards the interior for approximately 180 km. The Wine of Origin areas in which Mourvèdre dominates include inter alia Alicante, Bullas, Yecla and Jumilla. These regions are situated at between 38 and 40 degrees Northerly latitude and consequently receive more than enough sunshine and heat in particular. Mourvèdre is grown in two climatic regions especially; Mediterranean at the coast and continental as one moves further inland and the height above sea level increases. Although there are considerable differences between day and night temperatures in the interior, compared to the coastal zones, the differences in average daily maximum temperatures are insignificant, regardless of height above sea level of up to 750 metres. Day temperatures easily exceed 40 degrees Celsius during the ripening period.
Rainfall is low and in certain areas it borders on the minimum required for dryland viticulture. The average rainfall is between 350 and 450 mm per annum, which decreases to almost 320 mm in the areas that form part of the Meseta (interior plateau situated at approximately 700 metres above sea level). Mourvèdre is therefore cultivated in a dry, warm area with the accompanying low production levels. Due to the limited moisture that is available, vines are usually established as bush vines with wide plant spacings of 2.5 x 2.5 metres. This ensures that the roots are able to spread out over the maximum volume of soil in search of moisture during the warm summer months. The topsoils range from sandy loam near the coast to clay loam in the higher lying interior. Limey subsoils are widespread and constitute the secret to the performance of the vine. Vine roots flourish in the lime-rich subsoils (with pHs above 8) that are porous and deeply penetrable, with the result that moisture situated deep down in the soil can be accessed. This is the only way in which Mourvèdre, which ripens late (10 days after Cabernet Sauvignon), can successfully survive the tough summers of the Spanish east coast.
In the above-mentioned Spanish regions, Mourvèdre is used mainly in blends with Tempranillo and Grenache in particular, although lately it has also been blended successfully with Cabernet Sauvignon and Merlot. Traditionally Mourvèdre cultivar wines are only made from grapes from older vines with more pronounced tannins. Such vineyards are fairly common and many are still cultivated on own roots. The wine from young vineyards is usually especially fruity but not suited to maturation in small barrels due to its being inclined to oxidise easily, hence its use in blends with other cultivars. Mourvèdre is also used in large quantities to make red and rosé table wines that are harvested at lower sugar levels (and therefore higher fixed acid), as well as for sweet wines ("vinos de licor"). At home in Spain the cultivar is therefore very versatile.
Large plantings also occur in the south of France in the Lanquedoc-Roussillon area. This region is situated at about 43 degrees Northerly latitude with a predominantly Mediterranean climate. Temperatures in summer do not reach the same extremes as in Spain, but due to the late ripening of Mourvèdre it is dangerous to take chances by moving much further north. Incomplete ripening may become problematic at a higher latitude. In Lanquedoc-Roussillon Mourvèdre is used to a large extent in blends with Shiraz and Grenache. The wines have good colour and tannins, with prominent spice and berry flavours. The grapes are harvested fully ripe (at least 13% alcohol) in order to capture the unique characteristics of the cultivar.
South African conditions
The most obvious characteristics of Mourvèdre are probably its exceptional vigour and upright growth. The vines are easily recognised by their green-grey leaf colour and the white, felt-like underside of the leaves.
Most of the South African wine growing areas have more than enough sunlight and heat to ripen this late ripening cultivar without any difficulty. The area that shows the most similarities with the Spanish scenario (taking into account only the coastal areas with their Mediterranean climate) is probably the Swartland, where vines are mostly cultivated as bush vines without irrigation. Summer temperatures are fairly high and production low due to limited soil moisture. Rainfall ranges from 380 to 550 mm per annum. Only soils with sufficient water retention capacity can be used for establishment and this does not ensure that drought symptoms will not occur in certain years. Height above sea level ranges between 130 and 300 metres, with a typically Mediterranean climate.
Soils are predominantly shale in origin with granite at the foot of Paardeberg and the hills surrounding Malmesbury. The biggest differences between the Swartland and Spain are the soils. The granite soils have predominantly lower pH subsoils (below 5.5) and are not crumbly and penetrable by vine roots. Deep soil preparation and acidity adjustment by liming take place to a maximum depth of 1 metre, while deeper, natural root penetration in the lime-rich Spanish soils might be several metres. The clay-rich subsoils (from shale origin) of the Swartland have higher pHs and are more deeply penetrable, however, but they are often brackish (sodium, magnesium salts) and equally detrimental to deep root penetration.
Mourvèdre should be established in large volumes in the Swartland seeing that the hardy climate will keep growth and production levels under control. The cultivar is an excellent bush vine due to its upright growth. Vigour is such that 3-4 bearers may be pruned in the second season already. Fertility is good and the bunches are big, with large berries under luxuriant conditions.
It is fairly common practice to apply the first topping action early in spring (40 cm shoot length). Such early topping actions necessarily result in more secondary bunches on lateral shoots that must be removed before the harvest. Mourvèdre demands limited canopy control. A once-off suckering action is sufficient seeing that the vine produces few secondary suckers. Although the vine is a vigorous grower, growth is usually arrested in mid-December. A second tipping action may be required at this stage, whereafter the vine will no longer grow. Crop control to the desired levels is the only remaining action before the harvest.
Mourvèdre is late at budding (approximately 10 days after Cabernet Sauvignon) and ripens at a similarly late stage. The foliage has an "open" appearance due to limited regrowth after suckering and long internodes. The grapes are therefore exposed to direct sunlight from a fairly early stage and are particularly resistant to sunburn damage. The berries have a crackly appearance when ripe, with a thick skin. Flabby berries at harvest time are a sign of overproduction or moisture stress. Normally the grapes colour very well, although véraison is sometimes haphazard and drawn out (3-4 weeks). Take care that crop control is not too early, which may result in unnecessary removal of bunches.
Mourvèdre is usually harvested at full ripeness at 25+ degrees Balling. At these high sugars, acid levels tend to be relatively low at around 5 g/litre (at times even lower) with pHs of 3.5-3.6. Yield per hectare in the Swartland is never exceptionally high given the wide planting distances (3-3.3 metres between work rows). Production of mature Mourvèdre vines is about 3-3.2 kg/vine (8-10 tons/ha) on soils with good water retention capacity. It seems as though bunch and berry sizes decline with ageing vines, which is a very positive sign with regard to quality, especially if the cultivar is grown in irrigation areas.
The biggest percentage of Mourvèdre is currently found in the Paarl region, where it is being cultivated as trellised vines with supplementary irrigation. Due to the upright growth and strong vigour the vines are particularly easy to grow compared to cultivars such as Merlot and Petit Verdot. The exceptional vigour means that plant spacing should be adjusted. Care should be taken not to increase the in-row spacing too drastically as the vine has to support the grapes until late in the season. Increased crop load per vine could lead to unnecessary stress late in the season. Vigour tends to become more balanced with age and for this reason plant spacing of between 1.2 and 1.5 metres between vines is recommended. Obviously soil potential must also be taken into account.
The most suitable soil type for Mourvèdre is slightly idealistic and falls somewhere between a soil with growth limiting properties and a soil with good water retention capacity. Soils with a light topsoil texture (sandy/gravelly/stony) will restrain vigour, and medium to heavier clay subsoils for moisture retention are recommended. The cultivar is well suited to warm conditions, therefore the warmest slopes may be planted. If Mourvèdre is cultivated under irrigation on lighter soils, vigour can be easily controlled with judicious fertilisation and irrigation practices. It should be realised, however, that Mourvèdre reacts a lot like Shiraz to moisture shortages. The vine may already be subject to moisture stress without the foliage and grapes showing any such signs. Such symptoms usually occur after véraison only and may result in delayed ripening and worse, bevange grapes.
Trellis systems should preferably be planned using 2.4 metre poles. Two sets of moveable foliage wires that can be attached in at least 3 positions suffice since the cultivar is very resistant to wind and is a strong, upright grower. Since the bunches are carried high on the bearer shoots, more wires could pose a practical problem by complicating the harvesting process. Fertility is high and bunch and berry size above average, therefore Mourvèdre can easily overproduce when cultivated under irrigation. Acceptable production levels for quality range from 8 to 12 tons/ha (with 2.5 metre row widths). Potassium and magnesium shortage symptoms on the older leaves are a common occurrence towards the end of the season, but do not pose a serious problem, provided the levels of the elements in the soil are acceptable.
Mourvèdre fits well into the pressing programme since it is by far the red cultivar with the latest ripening. The late budding date also enhances the potential for establishment on soils that are subject to late spring frost. Mourvèdre is sensitive to downy mildew and oidium, but this poses no problems in dry areas. This is no reason, however, to presume that preventive control programmes should not be followed. When disease pressure is high, any cultivar is susceptible.
So far there have been no affinity problems with the commercial rootstocks R99, R110, 101-14 and US8-7. Mourvèdre is mostly grafted onto the more drought resistant rootstocks such as R110 and R99. 101-14 and US8-7 are recommended under irrigation only. In future Ruggeri 140 will probably also be used increasingly in the drier areas. Only one clone, MT11, originally of French origin, is currently available in South Africa. Other clones of French and Spanish origin especially are being considered as additions to the current selection.
General comments
Mourvèdre is a good example of an Old World cultivar with excellent potential in South Africa. The European scenario and the Western Cape wine regions definitely have a lot in common. The authors are not aware of any New World country that has conditions (climatic and production practices) so closely resembling as the Western Cape coastal regions (Swartland, Piketberg, Porterville, West Coast) and the eastern parts of Spain. The Mourvèdre wines made locally in recent years show great promise and Mourvèdre grapes are already in great demand.
The wines have a uniquely prominent fruity/spicy character with intense colour and have been used mostly with Shiraz in blends up to now, to provide an additional fruity component, which is undoubtedly the strong point of Mourvèdre. Most South African vineyards are still young and therefore the structure of the wines is not as clearly developed as will be case with older vineyards.
In Europe Mourvèdre is traditionally used in blends with Tempranillo, Grenache and Shiraz. At the moment the best potential for Mourvèdre in South Africa, as mentioned, is probably in blends with Shiraz until such time as the vineyards become older with the accompanying balance in vigour, production levels and structural development. Who knows, success may be had by using Mourvèdre in conjunction with Cabernet Sauvignon and Merlot, as in Spain. Local producers who have added a small percentage of Viognier to their Mourvèdre-Shiraz blends, have found the combination to be complementary. Some producers in Spain harvest Mourvèdre at low sugar levels so as to make more delicate, lighter style wines. This may also be an option for South Africa, especially taking into account the increasing demand for lower alcohol wines.
Mourvèdre is certainly one of the easiest cultivars to grow due to the above-mentioned upright growth pattern, vigour and minimal canopy management input. This makes it a "relatively cheaper" cultivar in terms of annual production cost per hectare, compared to for example Cabernet Sauvignon, Merlot and Shiraz. Suckering and other canopy management actions are undertaken considerably later than with other cultivars and therefore extend labour over a longer period. Crop control is an important aspect that could make or break the cultivar. Mourvèdre is fertile and will bear excessively with a resultant loss of quality if crop control is not undertaken.
Most South African viticultural areas are warm, therefore one might readily accept that Mourvèdre has potential in regions other than the warmer parts of Paarl and the Swartland. In the traditional irrigation areas of Worcester, Robertson, Klein Karoo and the Olifants River Valley there is undoubtedly potential since vigour and berry size can be managed with reduced irrigation techniques. Sufficient non-alluvial soil is available for the establishment of Mourvèdre.
Interesting wines could also be made in the relatively cooler areas where establishment occurs on steeper, warmer northerly and north westerly slopes with well-drained, gravelly/stony soils. Mourvèdre is less susceptible to the occurrence of the negative "green" flavours that are sometimes found in Cabernet Sauvignon and Merlot from cooler areas.
According to the latest SAWIS statistics of 30 November 2001 altogether 32.98 hectares have already been established in South Africa, more than 60% being in Paarl and Malmesbury. Today's figure is probably much higher, seeing that the considerable hectares that were established in the 2002 season were not yet included in the above statistics.
Acknowledgements and literature
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