Why are there no plums on my tree?

Is your plum tree not producing fruit? Or are you wondering why there are no plums on your tree?

You can usually tell if your plum tree will yield ripened plums by examining the flowers immediately after the petals fall off. The ovary (which will become the fruit) is located at the base where the petals were. It should be swollen and enlarged. If it isn’t, there was a problem with fruit set which could be due to poor pollination, unfavorable weather, insect pests, or poor health of the tree.

Another plum tree fruit problem could be if the tree did not flower at all. It could be because of inclement weather, insufficient chilling hours, or the tree was too young. If your tree flowered, then started developing small fruit, but the fruit aborted, the problem could be pests or plum tree diseases.

Plum Tree Quick Picks

• Methley Plum Tree: Moderate size of roughly 20' tall and wide, thrives in zones 5-9
• Santa Rosa Plum Tree: Slightly more heat tolerant than the Methely Plum with a hardiness in zones 6-10
• Golden Plum Tree: Unique golden fruit! Grow this specimen in hardiness zones 5-10
• Scarlet Beauty Plum: Compact size of 10' tall and wide and loves the south, zones 7-10

Common Causes of Zero Plum Production

Your Plum Tree is not mature enough

Has your flowering plum tree been in the ground long enough to be well established? Plum trees typically begin to bear fruit when they are three to six years of age. Fruit develops earlier in some varieties and you even see baby plums begin to appear earlier in age. The fruit will continue to get bigger and bigger until it reaches maturity.

Pollinators are planted too far apart

If small plums form but fall off before maturing, poor pollination is likely the culprit. Check a dropped fruit for a seed (stone). No seed means the flower was never successfully pollinated.

Why Plum Trees Need a Pollinator

Most plum trees are self-incompatible, meaning they need cross-pollination from a different variety to set fruit. Even self-fertile varieties produce significantly more fruit with a cross-pollinator nearby. For best results, plant another variety within 50 feet that blooms at the same time.

Matching the Right Varieties

There are two main groups of cultivated plums, and they cannot cross-pollinate each other:

• Japanese plums (Prunus salicina) and their cultivars
• European plums (P. domestica) and their cultivars

Any two varieties within the same group will pollinate each other, as long as they're blooming at the same time.

What Reduces Plum Tree Pollination

Even with the right varieties planted nearby, these factors can hurt your fruit set:

• No bees present. Honey bees are the primary pollinators for plum trees. No bees means little to no cross-pollination.
• Bad bloom-time weather. Several days of rain, heavy cloud cover, or strong winds during flowering keeps bees inactive and reduces pollination.
• Insecticide use. Spraying during bloom drives off or kills the pollinators you depend on.

Encourage pollinators by planting nectar-rich flowers nearby and avoiding insecticide applications during the bloom period.

Insufficient Chill Hours: Your Tree Never Got the Signal to Bloom

Plum trees need a set number of hours each winter where temperatures sit between 32°F and 45°F, known as chilling hours. These hours don't need to be consecutive, but the total must be met before the tree will bloom in spring. Fall short of that number and the tree may not flower at all, or it blooms too early and a late frost wipes out the blossoms.

Chill Hour Requirements by Plum Type

• Japanese plums: 500 to 900 chill hours
• European plums: 700 to 1,000 chill hours (some cultivars are adapted to warmer climates)

Low-Chill Varieties for Southern Growers

If you're in the South or a warmer climate zone, look for varieties with requirements in the 150 to 300 hour range, including Santa Rosa, Golden Plum, Methley, Burgundy, Mariposa, Shiro, and Satsuma.

How to Check Your Location's Chill Hours

Chill hour requirements are listed on nursery labels and don't line up directly with USDA hardiness zones, so don't use your zone as a substitute. Use this interactive calculator to find the average chill hours for your specific location: http://agroclimate.org/tools/chill-hours-calculator/

Bad weather?

Exceptionally high winds or drenching rains in spring can damage buds or flowers, causing them to fall off and not produce fruit. Flower buds can be killed by an extremely cold winter. Choose plum trees adapted for your climate zone.

Unusually extreme cold or frost during or immediately before the blossoms open can cause them to wither and fall off. If this happens, there will be no fruit. Covering the tree with a lightweight fabric (such as Reemay®) can protect the blossoms from frost. To protect from extreme cold, you will need to cover the tree with something more substantial (like a blanket) and include a heat source such as an electric light bulb.

Plum curculio infestation?

Plum curculio (Conotrachelus nenuphar) is a small beetle that lays eggs inside developing fruits, causing them to fall before they ripen. Signs of an infestation include:

• Small crescent-shaped blemishes on the skin
• Hard, misshapen fruit
• Tiny larvae visible near the spots on closer inspection

How to Control Plum Curculio

Start with cleanup and prevention, then escalate if needed:

• Clean up dropped fruit immediately. Larvae develop inside fruit on the ground, so removing it breaks the cycle.
• Cultivate the soil around affected trees in late fall or early spring to destroy larvae overwintering underground.
• Shake the trees early in the morning when beetles are sluggish. Spread a cloth or paper underneath first, shake vigorously, then dump the fallen beetles into soapy water. A surprisingly effective method for small numbers of trees.
• Apply an insecticide if the infestation is severe. Effective options include carbaryl (Sevin), phosmet, malathion, pyrethrins, or the organic fungus Beauveria bassiana.

Important Spray Timing Rules

• Wait until all flower petals have dropped before spraying to protect bees and other pollinators.
• Reapply two more times at 10 to 14 day intervals.
• Do not spray close to harvest.
• Always follow label directions.

Other insect pests?

Plum sawflies, mites, scale insects, aphids, various moths, and other insect pests can infect plum trees and fruits, reducing or eliminating a crop. Many of these insect pests can be controlled by spraying the trees with dormant oil or neem oil in late winter. Dormant oil and neem oil are accepted organic pesticides. They work by smothering insects and their eggs. As always, follow manufacturer’s directions.

Brown rot

If the blossoms, fruit, and/or twigs and branches of your plum tree are covered with a dark brown slime, it is probably infected with the fungus known as brown rot (Monilinia fructicola). Brown rot will cause the plums to become soft and shriveled, and eventually drop off the tree. Remove and destroy infected fruit in late summer or fall. Remove and destroy diseased branches in winter. It could also mean infected leaves which will also need to be picked off.

Fungi like it humid. Keep your plum trees pruned to maintain good air circulation. When watering the tree, water the soil, not the foliage. If brown rot has traveled down to the soil level, you might need to talk to an expert.

If brown rot continues to be a problem, you may have to resort to chemical fungicides. Apply a copper based fungicide in early spring while the trees are still in their pink bud stage (before blossoms open) and again three weeks prior to plum harvest. Always follow label directions.

Tree vigor

Sometimes a plum tree just isn't getting what it needs day to day. Run through these fundamentals before assuming something more serious is wrong.

Sunlight Plum trees need at least eight hours of full sun daily. Avoid planting where they'll be shaded by buildings or neighboring trees, which also creates unwanted root competition.

Air Circulation Keep the canopy open and well-circulated. Poor airflow invites fungal disease and rot, two of the most common reasons a plum crop fails.

Water Plum trees need about one inch of water per week from rain or irrigation. Come up short and the tree may drop blossoms or abort developing fruit. When you water, soak the soil several inches deep rather than watering lightly and frequently.

Fertilizing Use a balanced formula like 10-10-10, or one that's higher in phosphorus (the P in N-P-K), since phosphorus drives blooming and fruiting more than any other nutrient. A slow-release fertilizer works especially well for consistent feeding throughout the season. Bone meal is a great natural way to supplement phosphorus specifically.

Pruning Prune every year in winter while the tree is dormant but before buds form. Focus on:

• Building a strong scaffold structure
• Removing crossed or rubbing branches
• Cutting out suckers at the base and watersprouts shooting up from branches
• Keeping the overall height manageable

Weed Control and Soil Maintain a weed and grass-free zone at least three feet around the trunk. Weeds compete directly for the water and nutrients your tree needs. In poor soils, a quality planting mix or soil amendment can make a significant difference in long-term tree health and productivity.

Excess Nitrogen Fertilizer

Nitrogen fertilizer promotes leafy, vegetative growth and can diminish flowering if applied in excess. Do not over-fertilize and always follow label directions when fertilizing your plum trees.

Alternate bearing: The Feast or Famine Cycle of Plums

If your plum tree produced heavily last year and is barely fruiting this year, alternate bearing is likely the explanation. It's a natural pattern where a tree puts so much energy into one big crop that it has little left for the next season.

The best way to reduce the effect is to thin developing fruit in early summer while they're still marble-sized. Space remaining fruit to one every four to six inches along the branches, keeping the larger fruits and removing the smaller ones. This moderates the crop load so the tree doesn't completely exhaust itself. That said, alternate bearing can't always be fully prevented, just managed.

Other Diseases to Watch For

If none of the above explains your tree's poor production, take a closer look at the bark and leaves. Two common plum diseases are worth knowing:

• Black knot: Abnormal swelling on twigs and branches that develops into large, dark cankers. This one can be fatal to the tree and will overwinter and spread to nearby trees if left untreated. Remove and destroy affected wood as soon as you see it.
• Powdery mildew: Shows up as a white powdery coating on leaves and branches, with leaves curling upward. Common across many stone fruit trees.

Fungicides offer protection from both. Staying on top of either disease early is far easier than dealing with a full infestation later.

Still Have Questions?

Plum trees are rewarding, cold-hardy fruit trees that grow well across a wide range of climates, including tough Midwest winters. If you've worked through this guide and still can't figure out why your plum tree isn't producing, reach out to us and our team will help you sort it out.

For a complete overview of planting, growing, and harvesting, visit our Plum Tree Grow Guide.

Happy planting!