People love magnolia trees for their pretty flowers, nice leaves, and stately shape. But different fungal diseases can affect the trunks of these trees, which could affect their health and appearance. This complete guide will teach you how to find, treat, and stop common fungal growths on magnolia trunks.
What Causes Fungus on Magnolia Tree Trunks?
Fungi are organisms that thrive in warm, moist environments. The main things that can cause fungus to grow on magnolia trunks are
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Wet conditions Excess moisture from frequent irrigation, rain, or poorly drained soil encourages fungal pathogens.
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Wounds and damage: Cracks, wounds, or pruning cuts create entry points for fungal spores.
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Poor air circulation: Dense foliage blocks air movement, resulting in increased humidity around the trunk.
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Weakened trees: Drought, nutrient deficiencies, or other stresses can make magnolias susceptible to fungal diseases.
Common Types of Magnolia Trunk Fungus
Let’s examine some of the most prevalent fungal growths that may appear on the bark of magnolia trees:
Sooty Mold
Sooty mold shows up on the magnolia tree’s trunk and branches as a dark, powdery covering. It is caused by honeydew that bugs like aphids and scales leave behind. Even though it’s not directly harmful, it can keep plants from getting sunlight.
Lichens
Lichens form gray, green, or orange flaky crusts on the bark. They are a combination of algae and fungi growing symbiotically. Lichens don’t damage the tree but can be unsightly.
Algal Growth
Slime flux or wetwood causes wet areas that are prone to algal growth. The algae appear as greenish mats that turn whitish as they dry. Bacteria deep in the wood cause the oozing flux.
Wood Decay Fungi
Various fungi can decay the woody tissues of the magnolia trunk. Signs include mushrooms, brackets, or conks growing on the bark and soft, crumbly areas on the wood.
Cankers
Cankers form sunken or cracked areas where fungal or bacterial pathogens have killed patches of bark and cambium tissue. The affected bark may ooze gum or be discolored.
Is Trunk Fungus Harmful to Magnolias?
Most of the fungal growths are primarily cosmetic issues that don’t seriously harm established magnolia trees. However, cankers, wood decay fungi, and algal growth indicate underlying problems that require attention. Severe infestations can impact vascular functioning, structural integrity, and overall tree vigor.
How to Treat Fungus on Magnolia Trunk
The key to managing fungal diseases is prompt treatment and prevention through proper magnolia care:
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Improve air circulation and light exposure around the magnolia trunk by thinning dense foliage.
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Control insect pests like aphids that can promote sooty mold and algal growth.
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Prune out cankered, cracked, or decaying bark back to healthy wood. Disinfect tools between cuts.
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To protect pruning wounds and get rid of some fungal diseases, use bordeaux mixture, copper fungicides, or horticultural oils.
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Water at the base of the magnolia to keep the trunk dry. Fix drainage issues and avoid overwatering.
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Fertilize appropriately to maintain vigor without forcing excessive growth.
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For severe cases, consult a professional arborist for trunk injections or other treatment options.
Preventing Fungus on Magnolia Trunks
Prevention is key to keeping magnolia tree trunks free of fungal growths. Here are some proactive measures to implement:
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Select disease-resistant magnolia cultivars appropriate for your climate. Avoid susceptible varieties like the cucumber tree.
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Plant magnolias in sites with well-draining soil and plenty of sun and air movement.
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Irrigate deeply but infrequently, allowing the soil to partially dry out between waterings.
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Mulch around the tree with a 2-3 inch layer, leaving a gap next to the trunk.
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Prune only during dry seasons using proper techniques to avoid unnecessary wounds.
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Check regularly for signs of insects, cankers, oozing flux, or other abnormalities indicating disease.
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Clean up fallen leaves, pruned branches, and debris to eliminate spore sources.
When to Call an Arborist About Magnolia Trunk Fungus
Consult a certified arborist if you notice:
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Rapid expansion of cankers or cracks on the bark
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Mushrooms or conks growing on the magnolia trunk
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Significantly decayed, softened wood
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Oozing wet flux not resolving over time
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Overall decline in magnolia health and appearance
The arborist can inspect, diagnose, and recommend the most effective solutions. Acting quickly improves the chances of saving valued magnolia trees.
Key Takeaways
Yellow Leaves With Brown Edges
If your lovely magnolia leaves look faded and yellow with dry brown edges, the culprit is probably the weather. It sounds strange to say that sweltering dry weather and very cold weather would cause the same thing to happen, but this is precisely the case.
Very cold, harsh winds have the same effect on leaves that drought has. The leaves appear to be burned because the water evaporates very quickly under these conditions, leading to those dry, brown edges.
It’s best to cut off as little damaged growth as possible and take extra care of the tree for a while. There is not much else to do after the damage is done. Some of these problems can be avoided by giving the tree enough water during drought. If the tree is young and small, you can cover it if you know it will be very cold.
Magnolia flowers have different lifespans from one species to another. Some types, like the huge Southern Magnolia, have a lot of flowers that bloom one after the other but only last one to two days each. Others, like M. in the spring, like the Japanese Magnolia or the Soulangeana. The purple magnolia blooms can last for a week or more.
If you are concerned about flowers turning brown and wilting, the first thing to do is determine how long your specific tree’s blooms last. If the blooms are opening and already have a brown discoloration or look wilted from the beginning, it’s very likely a climate issue. Once again, extreme heat or cold can put stress on a magnolia, affecting the blooms.
There is little to be done about the weather. The best solution here is to keep up with general tree health by watering, fertilizing, and pruning. A magnolia in optimal health will have the least reaction to environmental stress. Make sure to water weekly in times of extreme heat or drought.
If you live in a very cold climate, it’s best to plant your magnolia in a spot that has some shelter from freezing winds. It is the cold winds that typically do the most damage, not the actual temperature shift.
If a magnolia tree is not producing flowers, the issue could be related to sun exposure or soil pH. Magnolias need a fair amount of sun. Most types prefer full sun and will produce the most flowers in this situation.
Soil pH is a little more complicated but can generally be rectified without transplanting. Magnolias like slightly acidic soil. The soil’s acidity helps to break down the nutrients in the soil and fertilizer so that the tree can best utilize them. If the soil pH is too high, meaning too alkaline, the tree will likely become malnourished, and the first thing to suffer will be flower production.
When choosing a spot to plant your magnolia, ensure the area gets at least 6 hours of direct sun daily. If soil pH is the issue, a soil test will give you the necessary answers. Magnolias need a pH of around 6, give or take.
To raise the pH of your soil, add organic material like manure, pine mulch, or compost. Soil acidifiers are also available, but they tend to be more costly. Although they work faster, they do not last as long as amending the soil with organic materials.
Magnolia trees are not fast growers, to begin with. Expect to see 1-2 feet of growth per year, with smaller trees maturing at about 10 years and larger species taking as many as 60 years to reach their full height.
If your magnolia is growing at a snail’s pace, there could be various reasons, from malnourishment to pest infestation. If you’ve ruled out all the other growth-inhibiting magnolia tree problems on this list, nutrition is probably the culprit.
The short answer: fertilizer. But first, make sure your soil pH is right because if the soil is too alkaline, the nutrients in the fertilizer won’t break down in a way that makes them useful to the tree. Check the pH and then make sure you are fertilizing properly.
Magnolias don’t need a ton of fertilizer, but they do like a strategic fertilizing schedule and will flourish when given this. Magnolias should be fertilized 2-3 times during their growing season with a balanced fertilizer.
Spread a granular fertilizer (8-8-8 or 10-10-10 will work great) around the plant’s base in early spring, late spring/early summer, and mid-to-late summer. Fertilizing is particularly important during the tree’s early years.
Leaf and Branch Dieback
This leads us to the dieback of leaves and branches. First, rule out the normal shedding of leaves by a deciduous tree in the fall or an evergreen’s natural shedding in early summer before the flowers bloom. If the leaf drop seems untimely, and entire limbs begin to turn brown and lose leaves, you may have a more serious magnolia tree problem.
The most likely culprit of this in an evergreen magnolia is cold damage. If you had a particularly cold winter, there might be frost damage to some of the outer limbs. Evergreen magnolias are cold tolerant to a certain point, but prolonged periods of extreme cold weather can cause death of the younger growth.
Once the threat of freezing weather passes, prune off dead branches and allow the tree to recover. Giving the tree some fertilizer will help it to produce new, healthy growth, and it should be back to normal by the end of summer.
What is this fungus on my magnolia tree leaves?
FAQ
How to treat fungus on magnolia tree trunk?
Fungicides may be applied if there is evidence of a fungal disease present on your tree. An application of a copper-based fungicide or the Eco product Eric has recommended could be sprayed at leaf fall to kill any fungal spores hiding in the bark or developing buds.
How do you treat fungus on tree bark?
How To Eliminate Tree FungusVinegar Spray – You can create a highly effective fungicide by combining one tablespoon of vinegar with one gallon of water. Baking Soda Spray: Mix one teaspoon of baking soda with one quart of water to make this spray. Milk Spray – This remedy is one of the simplest!.
How to treat powdery mildew on magnolia?
Powdery mildew fungicide: Use sulfur-containing organic fungicides as both preventive and treatment for existing infections. Trim or prune: Remove the affected leaves, stems, buds, fruit or vegetables from the plant and discard.
How can you tell if a magnolia tree is diseased?
Premature shedding of leaves is frequently seen as the tree disease spreads through the magnolia tree’s foliage. If you see dark veining, blossom, and stem tip dieback then contact a tree care specialist immediately! Cankers are wounds and sores that can develop on stems and branches.
Do magnolia trees have fungus?
Just like many other plants and trees, Magnolia trees are usually attacked by various diseases and pest infections. It may also fall victim to fungal issues. The treatment done for fungus depends on the condition it suffers from. Here are the different fungal problems to learn about and how you can treat it: 1. Leaf Spot Diseases.
How do you know if a magnolia tree has fungus?
Identification Tips: As the name rightly suggests, the most common symptom is wilting of the leaves and branches. Initially, the leaves turn yellowish with brown margins and develop a scorched look. In magnolias, the sapwood develops a brownish stain, when a tree is infected with this fungus.
Are magnolia trees immune to fungal diseases?
To lower the humidity level around the tree, space out trees and shrubs or thin out thick foliage to let more air flow. In conclusion, while magnolias are majestic and beautiful, they are not immune to fungal diseases.
What causes black fungus on magnolia trees?
Black fungus on your Magnolia tress is likely one of two things: sooty mold or black mildew. Sooty mold is more severe than black mildew and they require different treatments to remedy. Learn the differences between these two fungi so you can identify the problem with your Magnolia tree.
What causes brown spots on magnolia trees?
Leaf Spot Disease Leaf spot on magnolia trees is a common fungal disease characterized by small, round, brown spots on the foliage. This fungus primarily targets the magnolia leaf during wet conditions. The presence of brown leaf spots, often surrounded by a yellow halo. The spots can merge, creating larger blotchy areas on the leaves.
Do magnolia trees get diseases?
Unfortunately, their beauty can be marred when disease-causing pathogens infect magnolia trees. Sometimes magnolia diseases can be pretty innocuous, while other times they’re fearsome, hard-to-beat afflictions. But no matter the disease you’re fighting, there’s almost always something you can do.