Why Prune and Train Your Apple Trees?
- To shape and balance your tree’s form
- To open the tree to light and air circulation
- To improve fruit quality
- To control vigor
Stake all your fruit trees. Use posts that will be at least 5′-6′ tall at finished grade. We live in a windy place; the stake not only should be used to hold the tree up but more importantly it can be used to hold the fruit up. The varieties we sell often begin bearing fruit in the trees’ second year. You may have the fortune of being the recipient of 10-15 lbs of fruit in the second year, but if your tree isn’t staked, it will probably be destroyed by the weight of the fruit even before the wind has a chance.
Use your tree stake as a training tool. Tie the trunk of the tree to the stake just below the first branches. Tie the leader to the stake every 18″-2′. For all tree tying, we recommend using an expandable material that won’t cut into the tree as it grows.
Stretch Tie is a commercial orchard product designed for this purpose, available at the nursery.
Pruning- General Rules:
Pruning is a requirement for success. Fruit trees were bred over many decades to bear on young wood. In apples, the most productive wood is 2-5 years old. Pruning not only shapes the tree, but also determines the quality and quantity of fruit.
Utilize training into your pruning program for the best success.
- If you prune into one-year wood you will delay fruiting of that branch
- If you prune into one-year wood, the net effect will be to make more one-year wood.
- If your goal is to produce fruit, don’t prune into one-year wood after the planting
- Unpruned one-year-old wood will develop many flower buds in its second year
- Pruned or headed one-year-old wood will develop almost no flower buds in its second year.
It is important to let the one-year wood grow into two year old wood. Does that mean letting the young branch you think you should shorten get too long? In some cases, yes. In the second winter you can cut the branch back to the desired length. Make sure when you prune, you are cutting into the two-year old wood. Pruning does decrease your tree’s fruiting potential by removing wood from the tree, but is necessary for fruiting success.
- Limb spacing (Branch Placement) on dwarf and semi-dwarf trees (the importance of Branch Placement is discussed below)
- Bottom set of branches should be about 26″-36″ above the ground.
- Lowest set of branches should have 24″ min and 36″ to the second set of branches. All other sets of branches only need 2 feet between them.
- Limb spacing (Branch Placement) on mini-dwarf trees
- Bottom branches should start at 24″. All other sets of branches should have about 12″-16″ between them.
Controlling branch vigor
Branch vigor refers to how strongly a branch is growing. Three major factors control branch vigor and flower bud formation: branch placement, branch angle, and caliper. These three things interact to balance and counterbalance growth within the tree.
- Branch placement (elevation) in tree. The lower the branch in the tree, the less vigor the branch has. The top of the tree will always be the strongest growing part of the tree
- Branch Angle. The more upright the branch, the more vigorously the branch will grow. If you take a vigorous branch and pull it down to a horizontal position, you can nearly stop all of the growth in that branch. We use a UV degradable tree training band for this, available at CMFC. Conversely, if you need a branch to grow more vigorously, pull it into a more upright position for a year.
- Caliper (thickness of branch). When comparing two branches in a tree, if the branches are the same elevation and growing at the same angle, the thicker branch will be more vigorous. This is why it is important to maintain older branches in the bottom of the tree.
You can control branch vigor by manipulating these three factors.
- Branch angle is the easiest way to manipulate branch vigor. By pulling upright branches more toward horizontal, you can decrease vigor. Experiment with branch angle to manage your fruit trees’ vigor. Ideal branch angle for fruit bud production should be between 60 and 90 degrees (90° is horizontal).
- Remember that branch caliper plays a key role in the vigor equation. Think of branch thickness as the width of a road. The wider the road, the more cars you can get down the road, or in this case energy (growth) though the branch. In an ideally shaped central leader tree, the lowest branches will be the thickest, and the topmost branches will be pruned and trained to reduce vigorous growth and encourage short, less vigorous, productive branches.
Prune your tree at planting (when planting bare root)
Why? Fruit trees that are bare root have had most the tiny feeder roots cut off during the digging process. If the leaf surface is not reduced via pruning during the dormant season, the tree will become moisture stressed when the tree begins to leaf out. The tree may take 6 to 10 weeks to regenerate feeder roots. If you don’t prune your tree then the leaf surface will overtax the tree’s ability to draw water up from the roots.
Central leader tree form
This is one of the easiest forms to train dwarf and mini-dwarf apple trees. A Central leader tree form is similar in shape to that of a Christmas tree. The bottom branches stick out farther from the trunk than those at the top of the tree. The suggestions listed below apply directly to this tree form, however the concepts can be used with any pruning- training system.
- Choose 3 to 5 branches that radiate from the trunk and are evenly spaced around the tree. These branches should be as close to the same thickness at the base as possible. (Remember that the greater the diameter of a branch the faster the branch will grow.) Branches that are growing in a horizontal habit tend to be more fruitful than upright branches. Next prune all of these branches to 18″-24″; if the branches are only that long or slightly shorter then no pruning will be required.
- Pruning the leader at planting- First you must select one upright shoot to become the leader. It doesn’t have to be the straightest shoot nor the strongest shoot; in fact, we tend to choose a shoot that is closest to the caliper of the side branches. Prune off all other upright shoots. Then prune the future leader to 8″-10″ above the highest branch on the tree.
Pruning the tree’s central leader: year 2 and up
On the leader, make a pruning cut leaving a side shoot of one-year-old wood, and leave that side shoot unpruned. This means the side shoot can’t be too long; 4″- 15″ is ideal. On older trees, this is the preferred cut to use to manage the leader.
If the leader shoot is long enough that it needs to be tied, it is best to bend it to approximately a 45-degree angle and tie it to the post. Left unpruned and trained at this angle, the shoot will push many fruit buds and many short, weak, productive branches. This will enable the top of the tree to fruit a year earlier. The best way to reduce the vigor in the top of a fruit tree is to produce lots of fruit in the top.
Open center tree form
We can apply the same pruning principles to open center trained trees. This training system is often used for semi-dwarf and semi-standard trees where a central leader tree would grow too tall to manage. Open center trained apples have multiple leaders, spreading out the trees’ energy. An open center apple should have 3-5 evenly spaced leaders. Each leader should be similar in vigor. If one leader is too vigorous, the tree will become unbalanced. The vigorous leader can be pulled a little flatter to decrease vigor, or a less vigorous leader can be pulled more upright to increase vigor.
Prune at planting, choosing 3-5 evenly spaced branches (if the tree has branches) to form the leaders. If you are planting an unbranched whip, cut the tree back just above where you want your leaders to form. The branches should ideally be at a 45-60° angle (90° is horizontal). If the leaders are flatter than this, the weight of the fruit is more likely to break them.
Like in central leader trees, large caliper branches that develop high in the canopy of an open center tree must be removed. Each leader needs to have the thick branches low down, with thinner branches higher up. Branches and spurs are thinned to keep all the fruit buds open to light. The principles of branch angle, caliper and placement seen in training central leader trees apply, but you are working with multiple leaders instead of just one.
When working with open center trees, one more aspect must be maintained; all the leaders must be close to the same height. If one leader grows too much taller than the other leaders, it will gain apical dominance and grow out of balance. To help balance the vigor in the leaders, sometimes you will pull down/flatten vigorous ones, and pull up weaker ones. This position training usually takes affect quickly, within a year.