16 Common Mulberry Tree Problems and How To Correct Them

A robust mulberry tree has the potential to survive for more than 50 years and yield a bountiful crop of delectable mulberry fruits on an annual basis.

When subjected to poor growing conditions though, these trees can become too stressed to produce fruit or even grow well at all.

To ensure your mulberry tree can live up to its best, here are 16 common issues to be mindful of and how to fix them.

Dealing with mulberry tree problems is rather common, but the heart of the issue is often pests or disease. Learn the signs to look for and how to help your tree survive in my detailed guide, Mulberry Tree Diseases, Pests & Problems.

1. Mulberry Leaves Curling

Curled-up or wilting leaves can be a sign of stress due to imbalanced watering or shock due to a snap frost.

Give your tree a deep soaking whenever the top 2-3 inches of soil feel dry, and ensure the soil doesn’t remain soggy, which can lead to root rot.

Also, provide a layer of mulch around the roots to help retain moisture (this offers frost protection too!)

2. Mulberry Leaves Browning

Leaves can turn entirely brown due to things like underwatering or overwatering, leaf scorch disease, or being in constant heat.

Mulberry trees won’t fare well in temperatures above 90ºF, so avoid planting them in regions higher than Zone 8.

Additionally, maintain balanced watering practices, and deter leafhoppers from your garden as these bugs transmit the bacterium that causes leaf scorch.

3. Mulberry Leaves With Brown Tips

When just the tips of mulberry leaves are brown, this can often point to drought stress or excess salt in the soil. In periods with little to no rainfall, it’s important to give the soil a thorough drink with about an inch of water.

This can help flush out excess salts leftover from fertilizer too.

Soil can suffer from fertilizer burn when too much is applied, so opt for a gentle feed of a balanced slow-release fertilizer (I recommend this one) in the spring, and water well afterward.

4. Not Growing Leaves

If some leaves are present but others haven’t caught up, cold weather damage could be the culprit.

If there are no leaves whatsoever in the growing season, it’s likely buds may have died off due to fungal diseases like verticillium wilt.

Encourage leaf growth and keep stress-related disease at bay by removing weeds at the base to eliminate competition for nutrients.

While the weather can’t be helped, keeping your tree well-watered, fertilized, and pruned every now and again will keep it in a stronger, leaf-producing shape.

5. Early Leaf Drop

When leaves are dropping before fall, it’s usually due to a lack of water or stress from diseases such as fungal leaf spot, which can occur after a wet summer.

In addition to keeping on top of your watering regimen to help nutrients reach the foliage, keep fungal disease at bay by pruning to provide good air circulation so that rain-covered leaves can dry quicker.

A full-sun planting location is also essential for these trees as shady spots only exacerbate disease symptoms.

Dozens of purple berries on a mulberry tree.

6. Poor Fruit Production

Poor weather conditions can often translate to a poor harvest of mulberry fruit. Harsh winds and extended warm seasons can stress and dry out the roots, causing the fruit quality and yield to suffer.

Protect young mulberry trees from the elements, and keep all trees well watered from blossom to harvest, keeping an eye on spring and summer forecasts to help determine watering frequency.

7. No Fruit at All

Did you know that it can take between 5-6 years for mulberry trees to bear fruit? If age isn’t the issue, improper pollination, pests, or water stress could be the culprits.

Boost pollination with companion planting (which incidentally can also help drive certain mulberry pests away!).

Also, maintain regular watering when the soil needs it to ensure your tree has the required energy to flower and fruit.

One thing to consider is the type of mulberry tree you have.

If you have a male tree, know that your tree will always be fruitless because only the female trees and those that are monoecious (bear male and female flowers) produce fruit.

8. Early Fruit Drop

Premature fruit drop is commonly seen on young trees due to the sheer weight on the branches. Mulberry trees produce an abundant crop of fruit that can be heavier than you might think!

Help it out by thinning out some of the young fruit using clean hand pruners, leaving about 6 inches between clusters.

Early fruit drop can also cause the secondary issue of messy paths, lawns, and sidewalks as the soft berries tend to stain every surface they come in contact with, so gather all fallen fruit before you start to tread mulberry juice everywhere!

9. Cracks in the Trunk

Trees younger than 10 years can have quite fragile trunks. Unfortunately, this can mean that strong winds and heavy rain can result in cracks in the trunk.

Older mulberry trees tend to lean with age, which can also cause cracks.

To prevent this, prune back some of the heaviest branches in late winter or early spring to restore balance, and provide sturdy support to prop up leaning trees into an upright position.

10. Uneven Canopy

An uneven canopy can result from improper or over-pruning or from overbearing fruit on one side.

Keep in mind that no more than say 25% of the tree should be pruned as more than this can cause considerable stress.

Using sharp, sterile pruning tools, remove any branches you find that are dead, diseased, broken, rubbing/crossing each other, or growing in an odd direction compared to the rest of the growth.

Dispose of trimmings appropriately to avoid spreading diseases.

Make structural prunes like this as needed every couple of years to help maintain a healthy structure and invite a good balance of air and sunlight to all the branches.

11. Water Stress

The health of your tree can suffer when soil conditions are too dry or too soggy. This can cause stressed or rotten roots, distorted foliage, and generally poor growth.

As a rule of thumb, trees should be watered deeply for the first 2-3 years (10 gallons per inch of trunk diameter ideally).

Once established, rainfall will suffice, and supplementary watering can be provided in periods of drought. Use your best judgment, and feel the top few inches of soil to see if it needs a drink.

12. Nutrient Deficiencies

Trees need nitrogen, potassium, and phosphorus, but when the ratio of these nutrients is out of balance, trees can display pale or yellow leaves or leaves may appear mottled and far from a healthy green.

Applying 2 inches or so of organic compost around the base every few months can help deliver a good balance of nutrients as it is rich in organic matter and drip-feeds the nutrients naturally.

If you do use fertilizer, always choose one with a balanced NPK ratio such as 10-10-10 to ensure the tree gets only what it needs.

13. Soil Compaction

Mulberry trees can adapt to many soil types, but a compacted, poor-draining medium isn’t one of them.

Heavy clay mediums have smaller particles than sand or silt, making it harder for water to reach the roots.

Amend these heavy mediums with organic matter like compost or pine bark to aerate the soil.

Better still, use loamy sandy soil mixed in with organic matter to create conditions that are both moisture-retaining and free-draining in equal measure.

Be careful working around the shallow roots as they are susceptible to damage, and damaged roots lead to even more tree problems.

14. Winter Injury

The harsh temperatures and storms during winter can cause leaves and stems to shrivel and turn brown, especially on younger trees.

Mature established trees can recover well and leaf out again the following season, but younger specimens will appreciate a generous layer of mulch around the roots to help them conserve moisture.

Covering saplings in protective horticultural fleece during severe winters can also help.

15. Bugs in Fruit

Even healthy mulberry trees are visited by pests from time to time. Fruit flies can be a particular nuisance as they lay their eggs inside the fruit and larvae eat their way out once they hatch!

Set up fly traps to stop adult flies in their tracks, and clear fallen fruit from beneath your tree to prevent potential eggs from overwintering in the debris.

16. Root Damage

Mulberry trees have vigorous root systems that can border on aggressive.

White mulberry trees in particular are considered invasive in the U.S. and are known to lift foundations and sidewalks due to their rapid growth rate.

Expansive root growth and subsequent damage are more likely when soil conditions are not study enough to bear the weight of the tree, leading to subsidence.

To reduce the risk, consider the soil geology beneath your home, and avoid planting trees or shrubs too near your property (a space of 29 feet is advised for a large mulberry tree).

Closing Thoughts

For the most part, mulberry trees are resilient and low in maintenance needs.

However, poor growing conditions and care, from improper watering to nutrient deficiencies and pruning mistakes, can contribute to poor foliage and fruit production and result in a generally stressed tree.

Keep yours happy and healthy with regular watering, timely pest and disease control, and balanced fertilizer use!

How great would it be if troublesome pests and diseases didn’t exist? Unfortunately, they do, and it’s up to you to help your tree recover when problems strike. Learn more by reading these articles next: