Buds and canes and shoots and spurs

Pruning methods is a topic I really struggled with for a while. What is the difference between spur and cane pruning ?  And why might one method be preferred over another.

The starting point is to understand how a vine comes to bear fruit. Central to this is the “bud”.  Buds are created on shoots around the flowering time. So as the shoot is busy making a grape bunch or two for the vintage year, by the time of that year’s flowering the shoot has already established on its length new buds from which shoots would grow the following year. During the vintage year each bud will develop a shoot and each shoot will typically produce one or two bunches of grapes.  (It is possible a bud may develop a primary and a secondary shoot - but for our purposes let us think in terms of just one shoot per bud). During the vintage year that fruit bearing shoot lignifies and itself becomes a cane, which will have buds along its length ready for the following years development into new shoots.  And so the process would continue uninterupted absent pruning.  The vine would each year develop more and more buds and thus yield more and more fruit.

The purpose of pruning of course primarily is to limit the number of buds since this limits the number of subsequent fruit bearing shoots growing from the buds, which in turn limits the number of grape bunches.

There are basically two ways do this. 

Cordon or Spur Pruned

The first is a system where the trunk of the vine has been trained to grow laterally /horizontally - on either one side or both sides of the trunk. This cordon has short “arms” along its length from which one or two shoots will grow. At pruning in the winter you cut down the lignified shoot (now called a cane - and there may be two) that emerged from each arm so as to leave just a single short part of one cane with two buds.  These buds grow new shoots in the vintage year.  Essentially one limits the number of buds by leaving each year after pruning just two buds on each of the cut back canes.  This small length of cane now containing two buds is called a “spur”- and several spurs run along the length of the cordon. After many years of accumulation these old spurs start to look like a small upward extensions of wood of the vine along the cordon - like ‘arms”.  This is “cordon” or “spur trained” method.  

Guyot or Cane Pruning

The Guyot method is different in that the number of buds is limited by allowing the full length of just one lignified shoot from the prior year (a cane) to remain on the vine during the vintage year. This lignified shoot will be trimmed the prior winter if it is too long so that along its length there are perhaps only eight or ten buds.  It is positioned horizontally along a wire. These buds produce shoots in the vintage year which are trained vertically on higher rows of wires. At the end of the vintage year this entire cane - which bore the fruit of the vintage - is wholly cut away.  To generate / have available a cane with buds along its length for the following year, each year at the time of pruning another cane is left with just two buds (for security - only one is actually needed). This is a single spur. This bud forms a single shoot in the vintage year, which in turn becomes the fruit bearing cane the following year. ( It would itself grow a single or pair of grape bunches in the vintage year - but its primary purpose is to be/provide the cane for the following year). If two shoots grow out of the spur then the pruner would simply chose the better of the two canes to set along the wire. Normally the side of the vine on which the two budded spur is left alternates so that the vine trunk over the course of many years continues to grow straight. 

The reason behind the nomenclature of each type does actually make sense. Cordon is spur pruned because one is cutting to leave many spurs each with two buds along the length of the cordon. You are pruning to create spurs. With Guyot pruning, one might think of it as cutting away all the canes after each harvest, leaving just one spur with two buds on the other side of the vine and one long cane which is horizontally tied to the wire. So Guyot pruning is not leaving spurs by partially cutting back many canes. Rather it cuts away the entirety of the canes and thus is called “cane “ pruning” .

Since Cordon training extends the trunk of the vine into its horizontal sections there is such more wood on a cordon trained vine than a Guyot trained vine, whose wood is essentially limited only to the truck itself. The smaller amount of lignified wood of the Guyot pruning method makes the vine less vulnerable to frost and as a consequence is the more popular of the two methods in cooler climates.  

Cordon pruning is capable of being pruned by machine or with a hedge clipper. Guyot pruning takes skill.  

There are many variants of Cordon pruning in particular. 

Bush trained / Head Trained. 

The third method is bush trained or ‘head trained”.  Essentially this is spur pruned - like Cordon - except there is no lateral extension of the trunk.  Spurs from previous years form in all directions directly from the top of the trunk and thicken up over the years to become arms.  

For great diagrams of these variants I suggest you go to Wine Folly’s website.