Monthly Report - June 2008

Sunrise over the vineyard

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There have been a few maintenance jobs to knock off, but this time of year you become a bit fixated on pruning.  By the next monthly report I hope to have it finished and have a well earned rest in August before all the fun begins again with the advent of spring.  During June I also managed to dig some test holes in the soil to see what effects we have had on the upper horizons of the soil profile in comparison to when we purchased the property.  We do have a deeper “A” horizon (which is the humus rich layer on the top), and a slightly more developed “B” horizon (the weathered soil underneath) – which is a good sign and indicates that mulching back into the soil the entire mid row growth has been beneficial.  Also the amount of worms in the soil has exploded and though I have no numbers to compare against, it does look like they have enjoyed the break from regular grazing as well.  There has been a push from many vineyard to put sheep amongst the rows early in the season so as to control grass growth and also add a bit of “manure” in the vineyard – we too may consider this in years to come, but there are downsides such as compaction from their little cloven hooves as well as loss of biomass that have to be considered as well.

 

Shiraz and the mysterious shrinking grapes…

 

At times I get quite exasperated by events in the vineyard that seem out of my control and just happen without rhyme or reason.  One of these events has been the behaviour of the Shiraz vines as we approach vintage.  For the two years previous to last vintage (2006 & 2007) I had given them an irrigation regime very similar to the red Bordeaux varieties, with watering a moderate amount during fruit set and the warmer days of January, before winding the water right back as vintage approached.  Even our moderate totals are very light on as it is simply to make sure the vines do not suffer irrevocably during their early years.  This chosen irrigating path was simply a shocker for the Shiraz fruit. The grapes simply halted the ripening process, and in both years the fruit did not produce the quality we would expect for high quality wine and were discarded.

 

So last vintage in response to this, and in discussion with a number of growers of the variety in the region, I increased the irrigation volume during the whole vintage.  The result is that this year we have produced some excellent fruit and all looks good for the following year as the pruning has shown much more even canopy growth.  But why?  I simply was at a loss to think that winding the water up would make the vines grow and ripen their fruit better, logic states you want the plant to go into water deficit to finish the season so as to get the grapes to ripen fully.  Well the answer was available to me the whole time and I had not realised.

 

Shiraz in France is almost solely grown in the upper Rhône Valley, and for years I thought this just a quirk of the AOC laws of France which controls which varieties can be planted where if you wish to name your wine of the Appellation.  There is no Shiraz plantings North and West of the Rhône, with even the greater areas of southern France (Midi, Provence etc), having limited plantings in comparison to its popularity.  Now why would that be?  Well the answer is in the climate, and it is such a simple solution I was quite dumbfounded.

 

The Shiraz of the Rhône Valley is located on generally quite steep slopes with a shallow soil and quite exposed locations.  It needs heat to get the most out of it, but also it needs rainfall, and not just winter rainfall but summer rainfall as well, as the subsoil can hold very little due to its rocky nature.  By reviewing the rainfall data from a weather station at St. Peray (near the vines of St. Joseph), the summers of the Rhône are generally quite wet with an average of ~400mm of rain falling between May and September, with the months of August and September often having over 100mm of rain each month.  In comparison to Margaret River we have an average of 240mm of rain over the months of September to March (our southern hemisphere equivalents), with February and March having an average rainfall of <20mm for each month.  No wonder our young vines were screaming out for a drink!

 

Now before I hear the screams of the dry grown brigade, it must be noted that there are few vines in Australia that are planted on such demanding rocky slopes as those seen in Hermitage, Côte Rôtie etc, thus their watering demand revolves around their age and depth of subsoil.  Deeply rooted old Shiraz vines of the Barossa and the McLaren Vale have access to groundwater at depth and as such this restricts the need to irrigate in any large amounts, if at all.  We too in 20 years may be in the same position and our Shiraz could quite comfortably live off the sandy clay regolith beneath our gravels – but for a little while longer we will use what the wines of France have told us and give our vines a drink as they approach vintage.

 

 

Winter settles in...

 

It has been a cool wet start to this year’s winter in Margaret River.  The cold fronts that have passed through have given us good rainfall totals, and between them we have had some lovely clear days as high pressure systems settle in and keep the area free of cloud cover giving us crisp clear mornings.

 

The numbers for the month and last year’s figures are provided below:

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June 2008:     

Avg Maximum Temp          17.9°C

Daily Max recorded            20.8°C

 

Avg Minimum Temp             8.7°C               

Daily Min recorded               2.7°C

 

Rainfall:                               161.3mm

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The 2008 maximum temperature average was very similar, but the minimum average warmer due to the greater level of cloud cover caused by the wetter conditions in 2008.  Rainfall is higher this year, and if rainfall continues during early July we should have our dam overflowing by mid July (last year the dam overflowed on 27 July).

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June 2007:      

Avg Maximum Temp          18.0°C

Daily Max recorded            21.5°C

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Avg Minimum Temp             6.9°C

Daily Min recorded               1.8°C

 

Rainfall:                             106.4mm

 

Pruning continues…

 

There is little else I can say really.  I will be out there cutting away with help from my wife and others (when I can lure them out), and hopefully the vineyard will be ready for another year by the end of July.  Our daughter Beth will be heading off to Cambodia this month to help with some missions, and if she remembers to take some photos I will post them with the next monthly report – it should be an eye-opener for her and her friends.

 

All the best everyone.

 

Cheers

 

 

Mark Gifford

Blue Poles Vineyard