Grape & Apple Pruning – How Could this Possibly be Interesting?
Jeana pruning Pinot Noir
How is it possible to write an interesting article on pruning? Why would anyone care? For me personally it’s something very simple but also very complex – art and science. If you eat fruit like apples, grapes, cherries, pears, blueberries or other perennial crops – pruning is part of what brings the fruit to market. In MOST cases pruning is still done by hand. As hourly wages rise, it starts to make mechanical options more viable – i.e. the machine can pay for itself quicker. Pruning is a significant farm event, period. Prune wrong, spend a lot of money. Prune wrong, sacrifice quality and quantity. In a positive light: pruning grape vines and apple trees is essential for maintaining their health, promoting optimal growth, and maximizing fruit production. Since we grow grapes and apples, that’s where I’m going to focus.
Keep in mind, I’m a 1st generation grape and apple grower at Chelan Valley Farms + lagriōth Winery. Fortunately, I’ve had the opportunity to travel to apple growing areas around the world (and grabbed some grape advice too) and learn from some of the best. That by no means qualifies me as an expert – please consider your unique circumstances when pruning. No variety is created equal.
Bud (apples or grapes): The part of an apple or grape plant that develops and contains all the necessary parts to develop into future fruit or branches (see pictures).
Apple Tree Buds
Shoot (grapes): single year growth (like a branch) that produces fruit.
Grape Vine Buds
Trunk (apples or grapes): the part of the grape or apple growing from the soil that acts as the foundation for the plant.
Rootstock (apples or grapes): in apples, rootstocks have been used commonly for over 100 years and originally focused on tree size. In grapes rootstocks were introduced in the 1800’s in Europe to help combat Phylloxera. By definition a rootstock could be defined as a different “plant” than the “variety” placed on top of it by grafting. Example: if a rootstock was named “Geneva” and the variety was named Cosmic Crisp® – you would graft the Cosmic Crisp® bud onto the Geneva rootstock. Rootstocks can control size, resist pests and disease.
Apical dominance (apples and grapes): apples are much more apically dominant than grapes. Remember, grapes are a vine. Apical dominance is the plants ability to pick out a part of itself to be the “leader” to reach for sunlight. The leading part of the plant actually then sends signals to the lower parts of the plant to say (in my words) – “Hey, rest of my plant part friends below, I’ve got this, you focus on absorbing light where you are, I’ll go for the sun.”. Think an evergreen tree – very conical in shape. Vs. how grapes can be bushier.
Grafting (apples or grapes): taking plant parts (typically needs to include buds on the plant part) from one “variety” and placing it on another. Let’s be clear, you cannot take grape buds (Vitus vinifera) and place them on apple (Malus domestica) – it won’t work. But you can take Cabernet Sauvignon and put it on Pinot Noir rootstock. You wouldn’t likely do that, but I use it to make a clear example.
What is the goal for grapes?
For grape vines, pruning serves several purposes:
1. Control growth: Grape vines can become quite vigorous, and pruning helps to manage the amount of growth to ensure the plant doesn’t become too unwieldy.
2. Increase fruit yield: By pruning, you can promote the development of fruiting wood and encourage the plant to produce more grapes.
3. Promote fruit quality: Proper pruning can improve fruit quality by ensuring that the grapes receive adequate sunlight and airflow.
What is the goal for apples?
Apple trees also benefit from pruning in several ways:
1. Promote fruit production: By removing old or unproductive wood, pruning helps to stimulate new growth, which can lead to increased fruit production.
2. Control tree size: Pruning can help to manage the size of the tree, making it easier to maintain and harvest.
3. Improve fruit quality: By promoting adequate sunlight and airflow to the fruit, pruning can improve the color, size, and flavor of the apples.
Key questions to consider pruning grapes:
Young or established?
Young vines. Are you just getting ready to plant a vineyard? First thing – get plants from a reputable nursery (like Inland Desert). Then understand what types of plants you’re going to receive. Will they be green potted, will they be dormant and bare root, will they be a taller dormant vine or a taller green potted vine. Each type of plant from the nursery will require a unique approach. I’d like to then think about young vine pruning in year 1, year 2 and year 3. This of course assumes you know your goal with how they’ll be trellised. Year one could be minimal pruning – in our case with the dormant vines, we planted them, helped them grow as much as possibly, then came back in February/March (technically year 2) and pruned them all back to two buds. Year 2, get them up to the wire and onto the cordon wire if possible. Year 3 hopefully you’ve either established spurs or this is the year. Spurs are part of how you’ll manage fruit in older vines (see picture). Pruning is critical the first three years but getting your plants to grow as much as possible is the total focus. No plant growth, no fruit, no fruit, no return on all your investment – no growth, then the pruning game changes.
Established spur in our 6 year old Pinot Noir on Chelan Valley Farms
Established vines. This is really where your trellis and training system comes into play. Let’s leave trellis and training systems for later. I’d like to focus on our Pinot Noir system. We planted 3.5’ x 8.5’ – unilateral cordon (cordon is the part of the vine that stays put on the wire). We’re spur pruning. What is a spur – well it’s what forms after you prune the first shoots you get to grow vertically. On the cordon, we want these spur positions to be about a fist width apart. And when we prune, we leave 2 buds per spur. There’s then a math equation on how much fruit that should produce – each spur has 2 buds, each bud produces a shoot, each shoot would produce 2 clusters on average. I could continue on here and the type of trellis systems could change this. What’s important is understanding your goals. Are you aiming for quality or quantity. With our Estate Pinot Noir the absolute goal is quality, therefore we don’t want to have too many buds or ideally too much fruit. Our thought with planting so dense was to give more horsepower to each vine to be able to ripen the fruit.
Rootstock or not?
Rootstocks in grapevines in Washington State are just now becoming a thing. The primary driver for planting “grafted” vines has been phylloxera. Phylloxera is a soil pest that destroys grape vines and is more prevalent in California. Our winters have typically been too cold for it. The benefits of grape vine rootstocks have evolved to include resistance to nematodes and other pests. In the context of pruning – rootstock choice can have a “physiological” effect on the “variety”. For example, it could change the maturity. Change maturity, you may want to consider crop load differently, change crop load – you may want to consider pruning differently.
I think this is a really big topic, i.e. I’m not sure how much time I should spend on it. But, I do want to emphasize this because it directly impacts pruning. And its really variety and style dependent. Plus consider where you’re growing. Are you going to have irrigation or not? Are you in an area where you’ll get excessive plant growth because of natural rainfall? These would all affect trellis system and vine training choice. Which in turn directly impacts how you’ll prune.
A deeper look at pruning apples:
A bit on apical dominance. This is a fun one. Many of our guests to the farm ask about pruning apples. They’ve got a couple trees or a bunch of trees at home. They’re not happy with the quality or the quantity of fruit they’re getting. One of the first things I like to teach about is apical dominance (see definition above). Keep in mind EVERY apple variety has different growth preferences. Some grow big, some grow slow, some bear fruit on the tip of the branch, some bear fruit near the trunk. Regardless of growth habit – apples like to establish a boss. On the modern trellis systems this becomes clear (see picture). On the old school self-rooted trees there ends up being a lot of bosses to prune off. What I’ve been able to walk people through via back and forth on photos is how to control the bosses. An example that sticks out is someone who shared a photo of their apple tree with multiple varieties and the branches were trained down horizontally – imagine like an old school TV antenna on the roof. As the tree grew each year, the small branches started growing up vertically from those horizontal TV antenna branches – they were trying to become the boss. Key lesson. Typically, vertical branches don’t produce fruit. The tree needs a “boss” – but not tons of them. The goal is to have a lot of horizontal, small branches. I’ve described this many times on the farm and had some folks share great results removing the extra “bosses”. Fun topic – hopefully it makes sense in a written form.
Our modern planting of Cosmic Crisp®. Planted 3’ x 11’ on Chelan Valley Farms
Young or established?
Like I talked about on grapes. Whether you’ve got an established planting or new planting – the pruning is very different. When we plant a new apple tree we’re focused on getting growth like in grapes and we’re also very focused on getting the structure we’re aiming for. On our latest planting of Cosmic Crisp® we planted 3’ x 11’ (that’s a lot of trees by the way). Year one we cut a lot of the branches off the new trees – down to a couple of buds at the base of each branch. The following year we had more to work with and had to watch for branch growth on the trunk. Its possible on these new trees to have places where branches don’t grow (blind wood). In the event of what we’d call “blind wood” we have an opportunity to “score” near buds on the trunk. Pretty cool eh. You actually make a cut and it helps tell the bud to “turn on”. During this years pruning we’re also watching for heavy branches that may have formed – we don’t want too big of wood. There’s also a method of summer pruning – we actually come in and “tip” the branches to get buds to form behind the cut. Year 3, we’re expecting fruit this year so our pruning at this point is a result of how we’ve established the tree the prior two years. Get rid of heavy big wood, fine tune the number of small branches to provide light and make sure the top of the tree isn’t crowded by removing some of the growth. Now that this system is established when we prune we’re looking for areas that need a new branches to replace an old one and we’re trying to maintain what we’ve established. Now contrast this with our 70 year old Golden Delicious trees (see picture) – and we’re back to talking about removing the bosses or in the pruning world, we call them “suckers” on these old trees. The crazy thing about pruning these old trees is how much ladder work is needed vs. the neat and tidy 3’ x 11’ trellis.
Our 70 year old Golden Delicious trees.
Rootstock or not?
Rootstock development in apples is a topic all on its own. Again, I want to emphasize – rootstock choice WILL impact tree growth, which will impact pruning technique. But let me tell a story on rootstocks. Michael Pollan does a great job describing the Geneva (Geneva, NY) rootstock program (go here and scroll down to learn more directly from Cornell). I’ve had the chance to work closely with the scientists and researchers at Cornell and am still impressed with what they’ve brought to the industry – really amazing. They’ve got acres and acres of original plant material – and you can order buds from them. I got to see some of the wild spiny original trees. Ok, back to the story. In the early 70’s scientists from Cornell made crosses from Asia (home of many apples – lots of wild options). Imagine these folks flying around in helicopters in Kazakhstan to find wild plant material to bring back to their research program. Then in the late 1990’s they released the first of the Geneva® rootstocks. These rootstocks can very much impact pruning. Some of them are very dwarfing, some vigorous. Again, going back to pruning, if you’re going to have lots of vigor, that might be a match for a weak growing variety like honeycrisp, but you’re going to have to manage heavy or big branches when you prune. For your tree at home – it most likely is on a rootstock. And now I’ve got you wondering, how do I know what rootstock I have. You may or may not be able to find out. That’s ok. Go back to the rule of the bosses. Remember – branches growing vertical don’t typically produce fruit. Branches growing flat/horizontal are more likely to produce fruit. And we want those branches to be smaller… big heavy wood doesn’t fruit either. The point with all of this is understanding what you’re working with – and there’s a difference between a commercial orchard and a backyard tree….
Before wrapping up… an answer to a common question:
Before I wrap up, I’d like to share a bit about mechanical pruning. This is a question that comes up. Something to keep in mind is size/scale of the farm. Small farms may not be able to easily justify the cost of some equipment vs. larger growers. There are apple growers who won’t put a tractor and a person on anything less than 40 acres. Vs. a small farm like us who has 7 acres of apples and 3.5 acres of grapes (Pinot Noir, Chardonnay and Sauvignon Blanc). Regardless – can we prune mechanically – answer – kind of. In grapes there are attachments for the tractor that can help remove some of the vine growth to make fine tuning the pruning simpler. And in the really high-tech space, there is “smart” equipment being developed that can do it all. Likely more effective in larger acres on flat ground (vs. hillside). In apples, its kind of a similar scenario. Although fine tuning the pruning isn’t something I’ve seen at all in apples. More energy seems to be focused on automating harvest of apples. And overall automation seems to be really ramping up in agriculture. Especially with the new overtime laws coming into effect which will make agriculture no longer exempt from overtime. Historically some farm workers could work 60 hours in a week during the growing season and take the winter off because there is no work. Another learning curve for farmers and another reason automation makes sense.
Conclusion: Boy oh boy when I started this, I didn’t imagine it would be this long. Our goal in writing these weekly is to inform, educate and help each of you. We really appreciate you following along. I don’t know if this article leaves someone with instructions on how to prune, but more about what to consider and different variables. Or maybe even more about – what is it you’re trying to accomplish? As with anything – there are lots of things to consider. Pruning is a huge operation for the farm and the largest growers I know are VERY involved with it. So if you feel overwhelmed with the couple of trees in your yard, that’s probably ok, there’s lots of decisions to make on where to cut…
Some resources you might find helpful:
Pruning Grapes in Home Gardens: Some Basic Guidelines. Great visuals and really gets into some nuts and bolts.
Pruning Tree Fruit – The Basics and, you can scroll to the bottom and request a video. This one is big picture sort of like this article but offers some good concepts.
OSU has a nice publication for home pruning. It offers some great visuals and defines some terms.