One of the most important reasons to prune pistachios is to encourage fruit production. But this is not the only thing, since other objectives of pruning are to facilitate harvesting, direct the growth and formation of trees, improve ventilation and facilitate the penetration of sunlight. Many people do not know what are the main guidelines to learn about the pistachio pruning.
For this reason, we are going to dedicate this article to telling you everything you need to know about pistachio pruning and what is needed for it.
When is the pistachio pruning?
Young pistachios are pruned during the first and second years to define their shape. Taking care of the shape of the tree is important because it affects the quantity and quality of the harvest, how easy it is to harvest and other agricultural activities. Prune ripe pistachios to keep their shape and clean the inside of the tree, which improves ventilation and allows sunlight to penetrate inside. All these tasks benefit the production of future harvested fruit.
If there is something that we have to take into account when pruning pistachios, it is if there will be frost after cutting. Pistachios, like other fruit trees, can suffer tissue damage when temperatures drop significantly after pruning. In this way, while there is a risk of frost (temperatures close to 0º), pruning should be delayed until the risk is reduced. Therefore, we must align pruning schedules with periods of minimum tree activity and growth.
Usually, the best time for pistachio pruning is early springbefore the tree returns to activity and when there is no risk of low temperatures. This will reduce sap loss and the wound will begin to heal as the growth phase approaches. In climates with mild winters, fall pruning may be a good option.
While major pruning, such as training, production, or renewal, should be done during the cool season, green pruning should not. The best time to green prune pistachios is in early to mid-summer, when it is hottest.
We need several tools to prune pistachios. The choice largely depends on the type of pruning and the size of the tree. Basically you need some pruning shears and a handsaw. If our pistachios are large, we will need stairs, in addition to the necessary safety elements. These are the main materials needed:
- Clippers: Cut branches up to 5 cm long.
- Saw: Saw branches from 5 to 20 cm
- Height trimmer: Prune high branches.
- Chainsaw: Cuts raw wood over 20 cm.
- Safety glasses, gloves and boots.
It is recommended to disinfect pruning tools before pruning. This will help prevent fruit tree diseases.
How is the pruning of the young pistachio tree carried out?
To prune pistachios, we first have to decide what type of pruning to do, and for this we need to know the age of the tree. Unlike pruning a ripe pistachio that is growing and needs training to prune, we have to think more about production and make harvesting easier. Well, if it is less than 5 years old, we have to prune the tree to guide its growth and establish the main branch.. From here, the pistachios will go to the production phase, where pruning is necessary to improve the quality of the fruit and make it easier to harvest.
Pruning is done during this period of development to guide the growth of the tree and define its structure. We will see the type of pruning that we have to carry out at this stage of development:
It includes directing the growth and formation of pistachios in the early years. As this is a fairly vigorous pruning, do it when the tree is quieter, that is, in early spring, or in autumn in areas where the winters are not too cold.
We will do this by:
- Year 1: We are going to cut all the branches so that the branches below can sprout.
- Year 2: Trim back the main branch a bit to 2/3 of its length. We will remove the branches that sprout from the lower half of the trunk and leave the rest.
- Year 3: We slightly cut the main shoot to 2/3 of its length and remove the shoots that grow towards the interior of the pistachios.
Its main objective is to establish secondary productive branches. To do this, we have to choose the 3 main branches on which the rest of the tree will grow. Branches should not be too steep to prevent them from breaking under future weight. Next, we will trim back the main branches a bit, about 2/3 of their length, and prune the suckers coming off these branches to determine the structure of the tree.
How is the pruning of the adult pistachio tree carried out?
Adult pistachios, those that are already in the production stage, are pruned to maintain their shape and clean the interior of the tree. Thus we facilitate the entry of light and improve its ventilation. They are what are called production models, so we will see what they are made of.
This type of pruning is designed to take advantage of the amount of sunlight captured by the canopy to improve the quantity and quality of the harvest.
Perform production pruning to clean branches and clear the inside of the canopy to improve light entry and ventilation. Thus, we will try to get a leaf cup with an entrance and an exit to increase the exposure to sunlight. In addition, we will prune the unproductive branches to allow new branches to grow and we will remove the branches that are growing towards the interior of the tree. The objective of this pruning is to increase the yield of the tree and obtain higher quality fruits.
Let’s see what production pruning includes:
- First, we will eliminate the largest suckers because they are not very productive and slow down branch growth.
- We should not remove all suckers. The weakest shoots located inside the glass will be left to shade the wood that forms the structure of the pistachio.
- We have to prune the lower branches because they receive less light and therefore bear less fruit.
- We have to wear glasses with light in and out so that we can increase our exposure and take better advantage of sunlight. We will also prune branches that are entangled within the canopy, as well as those that are damaged, broken, or diseased.
- Not all twigs can be cut in order to maintain the leaf/wood ratio. Thus we will avoid the excess of wood, which reduces the regeneration capacity of the productive branches.
This type of pruning is carried out on pistachios with signs of aging that they have been in production for many years, between 20 and 40 years. These symptoms can be:
- small yellow leaves
- Low performance
- Loss of leaves inside the tree
This is done to rejuvenate the pistachios and can be done in large or gradual steps.
- Substantial Rejuvenation Pruning: In the first case, what we do is remove all the leaves from the tree, effectively leaving the base and main branches of the trunk to grow back.
- Progressive rejuvenation pruning: It consists of pruning from the top of the crown to the base of the branches. It is done in stages, every 3 years we will cut one of the four main branches of the tree.
Green pistachio pruning
Green branch pruning can be done in summer. Although it can be done at any time of the year, it is usually done at the end of August, when there is little activity in the pistachio trees due to the heat. This is done to control the growth of suckers or suckers, removing those that do not work with pistachios.
I hope that with this information you can learn more about pistachio pruning and its characteristics.