Winter months are a busy time for olive growers in the region, with the end of harvest signalling the beginning of pruning season. Tree management is critical in the management of olive trees. Once harvest is finished, around the end of June, the task of pruning has to be tackled and ideally completed before spring when the trees need all of their vigour for blossoming.
Olive trees are generally quite hardy and resilient, they will produce masses of new growth through spring and summer every year, generating copious foliage as the tree gains height. This new growth is very important, producing fruit on its second-year growth. Keeping this new growth under control to maximise harvest, but not allowing the tree to grow too large or dense, is the art of the olive pruner.
Pruning an olive tree is about creating a structure often referred to as a ‘wine glass shape’, in other words leaving an open centre in the middle of the tree, a bit like the cup of a wine glass. This allows for air circulation and, importantly, for the sun to reach the inside of the tree, hence providing the vital nutrients to the ripening fruit.
With good sunshine hours in the Matakana-Mahurangi region, some growers have commented on the pace of growth and height of their trees and that they can’t reach fruit for harvesting. If trees are left to grow unpruned, their height can make harvesting fruit quite difficult.
The process of pruning is at times necessarily aggressive, with around 20-25 per cent of the tree cut away to maintain height and shape. You may notice around the area that some trees appear to be cut back to just a trunk to allow for a new canopy to emerge and the tree to be re-shaped over the following seasons.
We completed our harvest in early June following a great crop of olives, but haven’t really tackled the pruning, with the weather experienced in the months of July and August frustratingly hampering our efforts. The rain we have experienced in the region in the month of August is not making this job any easier. Warkworth had in just the month of August an average rainfall of 134mm, with peaks of 91.5mm recorded over just one day; almost half the monthly record of 200mm. As a result, the ground is sodden and the grove slippery. It is not advisable to be pruning in the rain and the process of getting rid of the pruned branches (commonly by burning or chipping) proves a real challenge. The last couple days of sunshine, therefore have been a welcome relief and we are now all systems go to complete our pruning.
As spring quickly approaches, the trees will start budding ahead of the delicate time of pollination in October; a new year cycle starting all over again.