Winter — Pruning
Winter is coming… ⛄️
As the first chills cast over the vines, we witness the winter transformation of the vineyard. The leaves, that have been working all throughout the spring, summer and fall converting sunlight into delicious nutrition for the vine and grapes, start to fall. Now that most of the vine activity has stopped and all the glory of the vine has transformed into a skeleton of wood, it is time to start preparing the vineyard for the next growing season.
One of the major activities during this time of the year involves pruning the vines. This means that we need to remove this year’s fruit shoots and decide how and where we want next year’s grapes to grow. Why do we need to prune anyway you ask? Well, grapes only emerge from one-year-old fruit shoots, which means that the existing canes themselves will not be producing any new grapes. If we would not apply any pruning, new shoots will start bursting out from the existing canes, producing a new collection of grapes. Like you can imagine, this can result in some pretty serious growth. After some years it will become very difficult to keep the vine under control as it keeps on growing and it needs to work harder and harder to supply the nutrient to all of its branches.
Although the above behavior could be, in some way, convenient; it is not ideal for growing grapes for wine production. No, we want to recreate those idyllic vineyards with nice and tidy vine rows… so our goal is set! This does, however, require a little more effort and requires us to spend a little more attention on pruning the vines to optimize grape growth.
Pruning is not only important to determine the shaping of the vine, but it is also vital to structure next year’s growth. During the pruning process we carefully select and set out how many buds and spurs we will keep for the next season to grow. As you may or may not know, quantity does not equal quality in the context of grapes. We could select a large number of buds, but that would mean that the vine would need to work harder to make sure enough nutrient flows through to shoots towards grapes. As a consequence, it could happen that the grapes are not fully ripe at the end of the season. On the other side of the spectrum, leaving too few buds could decrease the yield and could also have negative impact on the quality and ripening process of the grapes as too much of nutrients will be flowing towards the fruit. The key is to find a nice balance between the number of buds and the expected yield in order to get the best grapes for your delicious wine. Until now I haven’t found a magical formula to calculate this relation. I guess it’s a matter of experience and trying out different configurations to see the impact during the growing season.
When can I start? 📆
In general you can start pruning right after all of the leaves have fallen from the vine. This indicates that the productivity in the vine has stopped, and it’s going into its dormant phase. You have time until somewhere in February — March (or even later depending on your location) when temperatures start to rise and activity in the plant is resumed. Pruning the vine during bud burst does involve some risk because you could damage upcoming shoots and cause cane “bleeding” where it loses active nutrition veins.
As it goes with everything in the vineyard, the timing of the pruning can have an impact on the grape’s growing curve during the upcoming season. Depending on your variety, the bud bursting phase can start earlier or later. Pruning can have an impact on the start of this phase allowing the wine grower to regulate the growing season with the goal optimize the grape’s ripening process. If you have an early bud breaking variety, you can decide to prune a little bit later to delay the grape’s growing curve and make sure it can harvest the full power of the sun during the summer in stead of ripening very early. Another reason to prune later is to prevent frost damage. Spring frosts are devastating on the yield when your vine has started its bud bursting period. No buds, no glory, … 😜
In my own vineyard I have always started to prune in February. I wanted to make sure that all frost periods were long gone before the buds started bursting. The impact of this late pruning is that the bud bursting was also a little bit delayed in my case (in comparison to other fellow grape growers). However, last year I did face two issues that made me decide to do it slightly different this year:
- The climate here in Belgium seem to be changing year after year. To be more precise, during February temperatures already went above 10+ degrees, but in March and April they dropped below zero. I noticed that during these periods of higher temperatures in February, the activity in the vine started to increase and I even observed some small changes in the buds. This meant it became quite risky to prune. However, in March it continued to frost during the nights. Luckily we were able to cope with the dropping temperatures by covering the grapes during the night.
- I did experience some issues with ripening the grapes in time for harvest. At the end of the growing season, I noticed that not all grapes were fully grown and optimal for wine production. However, as the temperatures were dropping and rain was coming down on us, we made the decision to harvest the grapes anyway.
Both of the above made me consider to try pruning a little bit earlier this year. And so, on the 12th of December (which was a clear day and around 9 degrees Celsius) I took my scissors and went to the vineyard in my backyard.
Let’s do this 😍
All right! So now let ‘s start the pruning!! Hold your horses! We need to think this through… We already know that only one-year-old shoots will create next year’s grapes. So how do we make sure that these new vines will grow the way we want them to. Luckily many viticulturist have already discussed this topic during some (probably) philosophic conversations consuming a glass of delicious wine. There are several pruning methods, but in this post we will be talking about the Guyot and Cordon pruning method as they are applied the most.
Independent of the selected pruning method, it is key to determine the stage your vines are currently in. If you have bought some young plants to start your vineyard, it is important to first create a strong and stable base/trunk for your vines to grow on before starting some serious scissor action! In general this is the same for all pruning methods.
Take care of the young ones, you need! 🍼
If you are dealing with one-year-old plants, it is important to establish a stable trunk. So during the winter we will be cutting everything just below your first trellis line. All side branches on the main trunk are also removed. We should still leave a small number of buds on the main trunk which will burst and grow during the upcoming growing season. Don’t be scared, it seems like quite a drastic approach to cut so much of a young plant, but we want it to focus its energy on developing its trunk, not yet on growing our delicious grapes. Patience my friend, patience is key in maintaining a vineyard. This process is repeated every winter until you have a stable trunk which usually after 2–3 growing seasons.
I had to apply this principle to a couple of my vines because part of the vineyard was planted during the first quarter of 2020. As you can see in the picture below, the trunk is not yet fully developed, which means I need to wait a little bit more before I will be able to harvest the fruits of my labor (more my vine’s labor!). For these young vines specifically, I have cut down everything just below my first trellis line. All side branches have been removed, leaving only the trunk equipped with some buds that are ready to grow in the upcoming year.
Some TLC for the workhorses of the vineyard 👐
Now that the young ones are taken care of, it is times to take care of the other vines. They have working hard during the growing season and now require some maintenance to prepare them for the upcoming season.
Guyot Pruning
As mentioned above we will be discussing two popular pruning methods. The first one is the Guyot method also referred as cane pruning. This pruning method is believed to result in the best yield, but it also is the one with the highest impact on the quality of the grapes as it puts some stress on the plant. As you will notice in its explanation, the pruning method is based on cutting away almost ALL of the one-year-old shoots, except for a couple that will be further developed during the upcoming season. As you can imagine this puts a lot of responsibility on the vine as the growth of next years fruit shoots are resting on the one-year-old cane that is saved from pruning.
Isn’t that a little bit too drastic? Well, it does have it pros and cons. A pro is that you are always using a fresh set of canes that will burst out new fruit shoots. This means we can vary the yield and get a better vine balance (see above) because we are able to adapt the process year after year by, for example, increase or decrease the number of buds we leave on the canes. Contrary to this is the fact that the vine does not build any reservoir for nutrients, except for the main trunk. It needs to put in a lot of work of getting the nutrition towards the fruiting shoots and grapes.
An another advantage of the Guyot pruning method is its protection against diseases, moss and several kinds of fungi, … As we start with a new fresh cane every growing season we have less chances that some unwanted creatures from last years wood are infecting our top canes.
To start with the Guyot pruning method, we should always have 2 one-year-old shoots that we will be calling replacement canes. When pruning, we cut everything away except for the 2 replacement canes. Depending on the fact that you use a single or double Guyot system, you either select the best replacement cane (single) or both and bend them over the first trellis. These canes will now form the base for next year’s fruit shoots and grapes.
But hold on… how do make sure that we have replacement canes for next year? Good question! If you have a single Guyot system, you can cut the second replacement cane back until you have 2 buds left. These will be used to grow the replacement vines for next year. If you have a double Guyot system going, it is important to grow 3 replacement canes so you can use 2 to bend over and one to cut back to 3 buds for growing next year’s replacement canes.
Cordon Pruning
A second pruning method is called Cordon and belongs to what is called spur pruning. The general concept of this method is to establish 1 or 2 very established and stable base canes, called cordon. The cordon itself is almost never pruned throughout the lifespan of the vine. During the winter, each set of fruit shoot is reduced to a spur containing two or three buds that will provide the shoots for next season. As you notice, the main difference with the Guyot method is that we do not prune the base canes (cordons) and only the fruit shoots.
Because we always reuse the same base vine, this vine can grow out to be a real storage system for nutrients. This is of course very beneficiary for the young vines that will be growing on top. However, this also has serious consequences when the plant is effected by diseases such as lice, moss, fungi,… as cutting away an ill cordon means starting all over again!
If your goal is to cover a larger area with your vine, the Cordon pruning method is your way to go!. Thanks to cordon we can grow a very stable vine that can provide enough nutrients to a larger network of shoots and canes. This makes it a very popular method to create pergolas or similar larger structures.
The general method that is applied during Cordon pruning is to transform the fruiting canes to spurs (cane with two or three buds). Usually, you have 2 fruiting canes have been growing from the spur that was pruned the year before. Select on of the 2 fruiting canes (you can select the based on growth indicators, such as woodiness of the cane or the ones closest to the trunk) and cut this one down so that 2 buds are remaining. The other fruit cane can be completely removed from the vine. After completing the full pruning, each of the cordons should have a couple of spurs, each ready to develop 2 new fruit canes during the next growing season.
Which one should I choose? 💭
This is, of course, THE big question and I think it depends on the several characteristics of your vineyard such as:
- The shape of the vineyard and the available space to grow — Are you working towards creating a pergola and need some large healthy canes, or do you have a limited space that you will allow the vine to grow in? Or you more focused on growing grapes for wine and really want to dedicate the nutrients to fully optimize yield and the quality of the grapes?
- Characteristics of the vine — Some varieties tend to prefer one method over the other.
- Climate — Climate has an effect on several fronts. Meteorological phenomena such as rainfall and temperature do have an impact on the vine. In some cases climate characteristics can cause the right conditions for diseases to develop on the vine.
- Soil composition — Based on the composition of your soil your vines can benefit from having a nutrient storage system like cordons.
- …
Well in my case I did choose to apply the Guyot pruning method. Did I make a detailed analysis of the soil, the variety, the climate here in Belgium? …… No not really 😃. However, I did do some quick googling of my varieties and found that these varieties are usually grown using the Guyot method. And because the Internet is full of trustworthy people (cough) it seemed logical to me to try it myself. To be honest I am quite happy with the result. For the past 2 years, I have been able to successfully apply the method to my Leon Millot vines. They have always produced some very nice grapes and with a big enough yield to start creating wine.
For my other vines, for which the variety is Vitis Regent, I am still in the process of developing the trunk before choosing any method. I am thinking of applying the Cordon method to these vines to get some experience with both pruning processes.
TL;DR
Why?
- Shaping of the vine
- Optimize the nutrient flow of the vine and therefore the quality of the grapes
When?
- Starting from the time that the leaves have fallen and before bud bursting
- Not during frost periods
How?
- Make sure that vine first develops a stable trunk, this can take a couple of years. If this is the case, remove everything right below before the first trellis line and remove all side branches from the trunk but keeping couple of buds.
- Guyot (Cane pruning) — Remove the cane that hosts this year’s fruit shoots and replace it by a new cane that will host next season’s fruit canes. Develop 2 or 3 new replacement canes to use for next year.
- Cordon (Spur pruning) — Reduce all this year’s fruit shoots to spurs (shoot with 2 buds) and keep 2 permanent canes (cordon) for the spurs to grow on.
