Plum trees are the perfect first fruit tree for a home orchard. They are beautiful, fruitful, and easy to prune. You’ve done the work of finding the right plum variety and putting it in the ground. Now, this article will equip you to prune a plum tree from year one to maturity. Keep reading to learn all there is to know about pruning a plum tree!
Why Prune a Plum Tree
Fruits such as grapes, blueberries, or even peach trees will become unproductive without proper pruning. In contrast, plum trees can thrive even if you make a few mistakes when new to pruning.
So, why is pruning plum trees worth the time? Basically, neglected trees will be smaller and bear less fruit than a pruned plum tree, but here are four main reasons to prune a plum tree:
- To create a manageable shape that is open to sunlight penetration and air circulation. Nobody wants to fight their plum tree just to prune it.
- To develop a strong framework of scaffold branches that won’t break under fruit load.
- To remove diseased branches or damaged wood.
- To encourage optimal fruit production of high-quality plums through the stimulation of strong and healthy new growth.
Everything You Need to Prune a Plum Tree
Before you prune a plum tree, gather the equipment you need for the job. You can reuse all these products to prune other types of fruit trees, so invest in quality pruning tools that will last.
Here’s the equipment you need to prune a plum tree, along with my suggestion of where to buy it:
- Pruning shears: hand shears for soft shoots, water sprouts, twigs, and foliage.
- Orchard loppers: loppers are heavy-duty shears for tougher branches.
- Pruning saw: a curved saw case you need to remove a diseased branch.
- Pole tree pruner: a long-handled pruner to reach that uppermost branch without climbing on a ladder.
- Garden gloves: gloves are indispensable to protect your hands from bushy growth.
- Pruning sealer: sealer is optional, but can prevent infection of stumps or pruning wounds. Pruning sealer can also be used for grafting – it’s possible to add an apple branch to your plum tree!
Plum Tree Growth Habits
When you prune a plum tree, keep in mind that its growth habits are different than those of apples or grapes. Growth habits will depend on what type of plum tree you are growing.
European Plum Tree Growth Habits
European plums fruit on spurs that are 2 years old, and up to decades old. Therefore, European plum varieties such as the cherry plum and yellow plums like the Mirabelle or Green Gage are very forgiving. Even if you cut back wood from the current season, they will still bloom and bear fruit.
Japanese Plum Tree Growth Habits
Japanese plums fruit either on 1-year-old wood (much like peaches) or on fruit spurs. Varieties such as the Satsuma plum and Elephant Heart are very fruitful and up to half of the one-year-old shoots must be removed to prevent overproduction. Varieties like the Santa Rosa bear light crops and only one fourth to one third of new shoots should be pruned out.
When to Prune a Plum Tree
Most fruit trees are pruned during dormant season. This is not true for plums. The best season to prune a plum tree is mid summer during full growth. Why not prune a plum tree in dormant season? The answer is that plum trees are prone to fungal infection, including the infamous Silver Leaf disease. Pruning in summer means there are fewer fungal spores in the air. Plus, the tree has more energy to resist fungal infections.
The exact time for pruning is variable but a good rule of thumb is to prune a plum tree in June or July. If you live in a humid climate in summer, however, late spring is likely the best time for you. Orchard growers in Minnesota, for example, find dormant pruning to work best since fungal spores abound during humid summers. Consider bee-safe fungicides to help keep disease in check.
It can seem wrong to prune off branches and shoots with fruit on them, but resist the urge to leave the tree unpruned. There will be plenty of plums left!
However, there are a few times when dormant pruning is the better choice.
Dormant pruning is acceptable in the case of limb breakage or at planting time.
Broken branches should be removed as soon as possible, even in winter. It is better to make a clean cut and cover it with a wound paint than leave a jagged wound in the tree.
Newly planted trees should always be pruned for the purposes of tree training. You want to start growing the desired tree form right away. Pruning at planting time is always necessary for pruning whips, but some suppliers will prune larger trees ahead of delivery. To minimize risk of infection when you prune a plum tree at planting, keep these tips in mind:
- Do your initial pruning in late winter months or early spring before bud break. Choose a dry day when there will be fewer fungal spores in the air.
- Make clean, sloping cuts to keep water from pooling on pruning wounds.
- Watch carefully for silvering or frost damage as spring growth comes in.
While fruit thinning is not specifically considered a pruning task, it may be necessary for the production of quality fruit later on. Complete your annual pruning before you thin the plums, and don’t remove flowers from bloom in spring. Summer pruning will remove fruit-bearing stems, which may be all that is needed.
Why might fruit thinning be used for plum trees? A heavy crop of plums will weigh down even strong scaffold limbs. Furthermore, fruit quality is higher when fruit trees can concentrate sun energy collected by leaves into fewer maturing plums.
Plum trees are known for their biennial bearing. They will produce a bumper crop of plums one year and then take a year off to store up energy and grow. Proper pruning and fruit thinning can help even out fruit production year to year.
Here are the steps for proper fruit thinning:
- In May or June, if the tree is full of plums, remove some smaller fruit.
- Prune the plum tree.
- In early to mid-July, remove any damaged, bruised, or pest-ridden plums.
How to Prune a Plum Tree
You’ll use a different pruning method for each main type of plum. Japanese plum trees and European plum trees are the most common varieties of plums. Because these trees grow differently, they do best with different shapes.
Before you start pruning, keep two things in mind. First, always prune a healthy bud in the direction you want new growth, which is usually upright and outward. Make clean pruning cuts for healthy stubs.
Second, carefully select scaffold limbs as the framework of your tree. Scaffold limbs should ideally be at a 45 degree angle to the tree. Branches with narrow crotch angles can split off the mature tree under a load of plums.
How to Prune Pyramid Plum Trees
If you’ve bought a pyramid plum, pruning will look a little different for these small plants. Fan training is a popular method to spread out the lateral branches of a short tree among horizontal wires. This makes the tree a pretty addition to landscape, and makes tree maintenance easy.
Here’s the process to prune a pyramid plum tree:
- In the first year, cut a new tree to about 2 feet above soil level a, right above a bud. Make sure there are at least four buds below the cut.
- In the second year, cut the main stem back about 12-20 inches. Lateral shoots will have grown from the buds you left the previous season. Prune all these lateral shoots to a bud, about 10 inches long.
- If you’re using a fan training system, remove any branches to the front or back of your central leader and tie lateral branches to your horizontal wires.
- Prune the mature pyramid plum by cutting back the central leader 12-20 inches to control height, and prune lateral branches back as necessary.
- As always, remove dead, diseased, or crossing branches.
How to Prune a Japanese Plum Tree
Japanese plum trees should be pruned to a vase shape. This means you’ll have scaffold limbs pointing out from around a central trunk with an open center.
Here’s the step-by-step process to prune a plum tree of any Japanese variety:
- The first year, you’ll have a pruning whip or young tree that basically looks like a stick with buds. Prune the stem back to two or three feet above the ground. After the branches have grown a few inches, choose vigorous shoots as lateral branches of your scaffold whorl. Lateral branches should be evenly spaced around the tree.
- The first two or three years, cut back the scaffold whorl to 1 bud at the top and 2 buds at the bottom.
- Prune out diseased material or damaged wood, and crossing branches. Make clean cuts.
- Starting at the lowest limb, cut off suckers, water sprouts, and any shoots or stems growing in towards the center of the tree or on the trunk below the scaffold limbs. Also remove any secondary growth on the scaffold limbs within half a foot from the trunk. Leave upright shoots that are directed outward.
- Cut off one half to one third of one-year-old shoots from the previous season to avoid overproduction of fruit.
- Cut back scaffold limbs and upright limbs to a manageable height. Non-dwarf plum trees can grow twenty to thirty feet tall, so cut back tree height so you can pick plums. Plus, this activates phytohormones that will encourage fruit growth in the lower tree branches.
How to Prune a European Plum Tree
European plum trees should be pruned to a central leader shape. In a central leader pruning system, scaffold branches surround a single upright branch that is an extension of the trunk. In the summer, you’ll notice the tree canopy forms a pyramid shape.
Here’s the step-by-step process to prune a plum tree of any European variety:
- The first year, cut back a pruning whip to 28-36 inches above the ground. Choose an upright branch as the central leader, and a few evenly spaced branches to form the scaffold whorl.
- In the second and third years, choose strong and evenly spaced lateral shoots to become more scaffold branches. Keep these lateral branches cut back to about 10 inches, or 2 buds. This concentrates growth into the central leader.
- In the first two or three years, cut the scaffold whorl branches at the top of the tree to one bud, and the bottom branches to two buds.
- After three or four years the tree will likely be growing tall. Prune back the trunk 12 – 20 inches at a bud each year so fruit and vegetative buds concentrate in the bottom tree branches.
- Every year, cut out dead, diseased, or damaged branches. Also remove unproductive shoots and any crossing branches.
- Cut off suckers and watersprouts at their source.
- If the tree is still too tall or bushy, cut out old growth and secondary branches that grow inwards. Upright branches can be trimmed in length.
Tips for Pruning a Plum Tree
If the step-by-step pruning process didn’t answer all your questions about how to prune a plum tree, check out some of the common concerns below. No matter what type of tree you have, these pruning hints will help you troubleshoot.
How should I prune an overgrown plum tree?
An overgrown plum tree can seem like an intimidating bunch of branches and sticks. It is a major pruning job, but don’t worry! Within a few years you can detangle your tree and get it to a manageable height.
Here are five steps for pruning an overgrown plum tree:
- Remove crossing or dead branches and diseased limbs.
- Thin out the tree. Keep in mind the proper shape you are going for. Cut out excess lateral growth and any stems directed inwards.
- Can you see through the tree yet? If not, thin it out some more.
- Prune lower branches to be parallel with the ground and upwards facing.
- Cut tall branches down in height so fruit is produced in a reachable location.
Why does my plum tree not have fruit?
There are five factors that might lead to a fruitless plum tree. The good news is that most of these problems are easy to fix!
- Your tree might need a cross-pollinating variety. Look up whether your variety needs a pollinator, and if so, plant another compatible plum tree within 50 to 75 feet.
- Do you have a bird problem? If birds are eating your plums, wrap the tree in bird netting. This shouldn’t affect light levels or air circulation as long as you choose a netting that isn’t mesh.
- Plum trees can bear fruit biennially, with a huge crop one year and few plums the next. Prune a plum tree properly to thin out the fruit for more even production. Fertilize your tree to ensure it is getting all the nutrients it needs to bear fruit each year.
- The flower buds on your tree may have experienced freeze damage. This happens to the best fruit growers. Next year, if the temperature is going to drop below 32 degrees Fahrenheit, wrap a light cloth or a black plastic sheet over the tree to make a tent that will keep it warm.
- Does the tree get enough sunlight? Plum trees need sun to produce fruit. If the tree is still young, you might be able to move it. If not, plant a new tree.
Should I prune a plum tree if it might be diseased?
Fungus and bacteria are some of the worst pests that can plague a plum tree. Bacterial canker, leaf spot, Silver Leaf fungus, and other diseases can ravage a plum tree. The best way to manage these diseases is to remove unhealthy branches immediately, and carefully choose the time you prune. Inform yourself on plum tree diseases!
If fungal diseases plague your plum tree, remove diseased limbs and try pruning at a different time of year. Dormant pruning or summer pruning might be the right choice depending on which season is drier where you live.
How do I choose the right pruning angle for scaffold limbs?
Scaffold limbs should be at a 10 o’clock angle (about 45 degrees). As mentioned earlier, a sharper crotch angle will be prone to breakage, and a flat horizontal limb can drag fruit on the ground.
Now You Know How to Prune a Plum Tree!
Learning how to prune a plum tree is a simple, necessary, and rewarding experience. Just remember the shape you should aim for.
Excited for more plum content? Then check out our plum trees page for the latest growing tips, care guides, recipes, and more!