OUT IN THE VINEYARD – December 2008
Flowering continues across vineyards in the Margaret River wine region and this is certainly one of the longest flowering periods that most local vignerons have experienced. Usually it is not uncommon for most varieties to complete flowering in two to three weeks but this year we are already up to five and a half weeks and still have inflorescences waiting to come into flowering. This extended period of flowering results in uneven fruit maturity early in the season but will possibly even up as the weather warms and we progress towards vintage. Most vineyards will correct differences in fruit ripeness at veraison (colour change of berries) by simply removing obviously greener bunches in preference to the remaining coloured bunches.
The process of flowering is complex and is influenced by many factors. For instance, the start of flowering on a bunch is signified by the release of the protecting cap, which are in fact the flower petals. This process is technically called anthesis but we just simply call it cap-fall. When the inflorescence are matured, cap-fall will usually occur mid morning, and is triggered by changes in the turgor of the interlocking cells that secured the cap. As the temperature raises the petals become free of their bases; they can separate along the margins and curve upwards to release the stamens. The flowers contain both male and female functional parts and can be self fertilised without the aid of insects or wind.
Weather conditions at flowering will influence the timing and success of flowering. This year we are seeing a long period of flowering due to lower than average temperatures resulting in a slow release of caps and therefore initiation of flowering. There has also been rainfall that has resulted in caps not clearing the bunch and in many instances remaining on the berry as it matures. These phenomena add to the complexity of growing a crop of grapes suitable for quality winemaking and this is the challenge that we aspire to rise too…. who said “life wasn’t meant to be easy”!
This season we are aware of the need to be very observant for pest and disease. Most vineyards will have a regular monitoring program in place that will require visiting the vines every few days to check on the health and well being. These checks add to the confidence of producing a crop of premium quality grapes free from damage. The viticulturist then reacts to the monitored occurrence of disease and therefore reduces the inputs of chemical, fuel and labour within the vineyard, much better for the environment and the balance sheet.
Techniques involving the use of machines that remove leaf from within the canopy using pulses of air are also used strategically to remove caps from emerging flowers. In a cool and wet spring such as this year it is important to provide a canopy structure that gives the best opportunity in providing less opportunity for disease to occur and to allow development of a ripe crop for harvest in 2009.
Information courtesy of The Margaret River Wine Industry Association. Check out their website www.margaretriverwine.org.au or join their Love Notes monthly email update by contacting firstname.lastname@example.org
Margaret River Discovery Tours
Sean Blocksidge is the owner operator of the Margaret River Discovery Company, an avid photographer, blogger and South West WA ambassador. In 2010 he won Western Australian Guide of the Year and his tours have been rated the #1 thing to do in Australia on the Tripadvisor website for the past two years.