Is it time for a gentler approach to pruning? – Vineyard – Rob Saunders
With winter pruning in full swing, Hutchinsons’ Rob Saunders examines why the “gentle pruning” concept is gaining attention and how it could be of benefit ...
The four key principles of gentle pruning promoted by Marco Simonit have been around for several years and are increasingly finding favour among growers in many key wine growing regions, including the UK.
The concept centres around the objective of protecting natural sap flow within the vine’s vascular system, through a more sympathetic pruning regime that also minimises the risks of trunk disease infection. Essentially it requires growers to focus more on how the “plumbing” inside the vine is affected by pruning interventions on the outside.
Interest in the system has been partly spurred by a growing awareness that trunk diseases are a potential limit to production, and disruption to vascular tissue and sap flow after pruning may sometimes contribute to otherwise inexplicable vine-to-vine variability.
Furthermore, in the UK there is a fairly limited toolbox for controlling trunk diseases, so there is some sound logic behind the gentle pruning principles, which can be applied to all training systems.
The concept is broadly divided into the four key areas described here.
Key areas
Aim to develop a crown and branch structure that respects the vine’s natural growth habit, rather than making pruning decisions focussed wholly on selecting canes based on inter-nodal distances and diameter, but giving additional consideration to the position from which the cane grows.
This goes hand-in-hand with point one and requires growers to try and maintain good vascular flow around plants when making pruning decisions.
Crucially, it recognises that behind any cut, an area of die-back forms inside the crown called a “desiccation cone”, which can interrupt the natural route of the vascular system. Desiccation cones formed behind cuts on the top and bottom of stems, for example, could eventually create a tortuous, serpentine vascular system with a reduced capacity to feed the rest of the plant.
Growers are encouraged to develop the crown and make only small cuts that are able to heal rapidly. Avoid cutting into wood that is more than two years old, as these larger cuts are slower to callus when growth resumes in the spring, presenting a greater risk of infection, especially if large cuts had to be made earlier in the winter.
While it is often tempting to make cuts close to a bud, this final principle advocates leaving a small stub of 12-25mm when cutting two-year-old wood to protect the crown and preserve sap flow. It means the desiccation cone of dead material that forms after cutting will be in the stub (also called a “snag”) and not close to the bud, which could potentially compromise its viability.
A word on timing
Theoretically, the best time to do any pruning is just before bud break in spring, when rising sap effectively “washes” the cut before it calluses quickly.
But as any commercial grower knows, this is simply not possible for larger vineyards where pruning has to begin much earlier – usually in early winter – to ensure larger areas can be completed in time.
Any steps we can take to reduce the risks of infection with less reliance on applying paints or other treatments is worth considering, and may well bring time or cost savings in the future. So if there are areas of the vineyard still to prune, it is worth trying out some of the gentle pruning principles this season, even if it is only a small trial area to see how it works in your situation.
Any major changes to pruning regimes will inevitably take time to get right and to implement, and extra management may be required to ensure any seasonal hired staff are clear about what is required.
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