Peaches are very lively trees in general, meaning they have a considerable growth rate and produce a significant number of shoots even when still in the plant nursery. Thus, pruning and training are essential growing techniques that a peach grower should perform annually. However, there are also rootstocks available in the market with a reduced liveliness that produce trees that are much easier to handle and maintain their shape.
We have two main pruning categories.
- Tree training
- Production Pruning (winter pruning)
Training includes all the prunings performed in young peach trees during their first and second year to shape them into the desired form (crown skeleton). The shape is critical and can affect the level of fruit yield, the quality of the products, and the harvesting or other farming activities in the orchard.
The most common shapes of Peach crown-canopy are:
- The open vase or open-centered system (or the delayed vase)
The open vase consists of 4-5 main branches, formed at 20-27.5 inches (50-70 cm) above the ground and have a 60 to 80-degree angle with the trunk to facilitate mechanical harvesting. These main branches are selected during the first year and are cut back by one-half. The farmer removes all things that grow downwards or to the center of the canopy. Vertically grown limbs with strong growth should also be removed from the base. During the second year, the efforts should be focused on maintaining the general shape (given in the first year) and developing the secondary branches. In the open center training system, each scaffold branch has two secondary branches (6-8 inches or 15-20 cm apart). The tree crown configuration must be completed in the minimum possible time and with minor operations. In this system, the planting spacing is around 4.5 *2.5-3 m (up to 888 trees per hectare or 355 trees per acre). The open vase is preferred to other training systems, especially in fields with moderate to steep slopes (in hillsides).
- The (Quad) V form or the Y form
In the V training system, the peach trees have two scaffolds that grow at an angle of 30o from the vertical axis (1 left and 1 right), while for the Y form, the 2 scaffolds’ angle should be around 60o. The tree spacing is 3.3-7 feet (1-2 m) between the tree and 15-18 feet (or 4.5-5.5 m) between the rows (around 800 trees per acre or 1,900 per hectare). The V system allows higher densities compared to the Y systems. On the other hand, the Y-form trees are a bit taller and need a trellis for support. Generally, the final tree canopy height is around 3.6-4.3 m (12-14 feet).
These two systems are preferred and widely used in intensive peach orchards. Their greatest advantage is that this system allows higher planting densities in the orchard, increased production, and mechanization. Another major benefit is that the trees reach full productivity much earlier than the ones trained as an open vase. More specifically, the V-form trees reach maximum productivity at 5-6 years, while the ones trained as an open vase at 8-9 years. Moreover, the aeration and sunlight penetration is much better compared to an open vase canopy leading to fruits of higher quality (better coloring and higher sugar content and flavor). However, peach orchards with V or Y training have a higher establishment cost (the V higher than the Y) and have increased water needs (irrigation is essential). Moreover, problems in frost-prone areas were mentioned when this system was applied. The growers should also remember that having only two scaffolds increases the risk of losing half of the production in case of a disease or limb break (fruit thinning may be required).
Productive Pruning of Peach Trees
After determining the tree’s shape, the farmer needs to prune his/her peach trees to maintain that shape and balance vegetative growth (renewal of branches) and yield. Before starting pruning, it is essential to remember that the peach fruits grow on the shoots produced the previous year (1-year-old), and the following guidelines may be adjusted in the different training systems. Moreover, no pruning should be performed when the weather is wet or/and rainy, ideally before bud break and two weeks after the last frost.
To facilitate harvesting, trees should be maintained at the height of 10 feet (3 m) by shortening last year’s main branches by 25-30 inches (64-76 cm) (around 20-30% of their length). Additionally, the peach grower should remove branches that grow straight down, are parallel and too close to each other, or cross paths, and open up the inner part of the tree to improve aeration and sunlight penetration. Around 25% of the branches of the tree are usually removed. Spurs of peach can bear fruit for more than one year (up to 5 years). After a side shoot has been given as fruits for 3-4 years, we can remove it to promote rejuvenation and boost production. Be careful to leave 0.25 inches (0.63 cm) distance between the pruning cut and the flowering bud, and always keep an opposite 45o angle from the bud. All these activities should be performed during the trees’ dormant period in early spring. However, growers prune their trees to the petal fall stage in colder areas. Moreover, the peach grower is advised to remove all broken or infected branches yearly. At the same time, suckers or water sprouts should be removed when still short (2-3 times per year). All the previous operations promote fruit production in the long term. The frequency of mature tree pruning ranges from once a year to once every two years. Remember to sterilize your pruning shears and saws in alcohol, disinfectant, or 10% bleach solution when moving from one tree to another or/and after removing an infected branch.
Producers who apply heavy pruning also use thinning. Farmers apply light pruning to varieties with smaller fruits and keep 6-8 buds on each pruned shoot. Thinning is not required in this case. A complimentary pruning may be applied in early summer to remove deceased and damaged shoots and sackers.
Fruit thinning is usually required in peach trees to obtain fruits of superior quality and larger size since the tree tends to produce numerous fruits. At the same time, reducing the risk of limb breakage (due to excessive fruit load) and stimulating flower initiation for next year’s production is important. This practice must be performed in years when the environmental conditions have favored excessive fruit sets. In most cases, for peach trees, it takes place 60 days after the full bloom and has as a goal to leave a space around 6-10 inches (15-25 cm) between the peach fruits. As an alternative, the grower can thin by pruning the 1-year-old fruiting lateral shoots during early spring. Ideally, 20-25 fruiting lateral shoots should be left per each scaffold branch of the peach tree. This may be risky in areas with late spring frosts that can further reduce the viability of the remaining flower buds. Finally, thinning the fruits by hand is also possible and preferred by many peach farmers, but it is a laborious, time-consuming, and costly method. In this case, in years with high yields, the farmer may need to remove even half of the small peach fruits (1-2 cm or 0.4-0.8 inches diameter) to succeed in the suggested spacing. Keep in mind that chemical thinners are not common for peach thinning.
How to Train and Prune Peach Trees