Magnolia campbellii Yellow Leaves - Causes & Fixes

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Iron Chlorosis (Nutrient Deficiency)

Magnolias have a high demand for iron; if the soil pH is too alkaline (above 7.0), the tree cannot absorb iron, resulting in interveinal yellowing while veins remain green.

Very Common

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How to confirm: Check if the yellowing is restricted to the leaf tissue between distinct green veins on young leaves.

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shopping_cart Recommended Products

1 Test your soil pH to confirm if it is above 7.0, as alkaline conditions prevent iron uptake.

YAMRON 4-in-1 Digital Soil Tester

Water Meters

$33

In Stock

2 Apply an iron supplement or chelated iron to the soil to provide immediate, absorbable iron to the roots.

FoxFarm Bush Doctor Cal Mag Liquid Supplement 1 Pint

0.5 L • 1 pcs • Organic

$22

In Stock

3 Amend the soil with organic matter like compost or peat moss to help lower the pH and improve nutrient availability.

Espoma Organic Potting Soil Mix

15.1 L

$22

In Stock

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Improper Soil Moisture (Water Stress)

Campbell Magnolia requires consistently moist but well-draining soil; both prolonged drought and waterlogged roots can cause leaf yellowing and eventual drop.

Very Common

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How to confirm: Insert your finger 2 inches into the soil to determine if it is bone dry or saturated with water.

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shopping_cart Recommended Products

1 Check the soil moisture level at the root zone to determine if the plant is suffering from drought or waterlogging.

GROWIT Soil Moisture Meter SMM-V3

Water Meters

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2 If the soil is bone dry, water the plant thoroughly; if the soil is saturated, ensure the pot has adequate drainage or repot into a well-draining medium like Espoma Organic Potting Soil Mix.

Espoma Organic Potting Soil Mix

15.1 L

$22

In Stock

3 To prevent future water stress, use a saucer to catch excess water and avoid letting the roots sit in standing water.

Bleuhome 10" Plant Saucer 6-Pack Black

Pot Saucers

$20

In Stock

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Root Rot (Phytophthora)

In heavy or poorly draining soils, fungal pathogens can attack the root system of Magnolia campbellii, leading to systemic yellowing as the plant loses its ability to transport water.

Common

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How to confirm: Examine the base of the trunk for any dark, water-soaked lesions or mushy bark texture.

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1 Immediately inspect the root system for mushy, dark, or foul-smelling roots and prune away any decayed sections using sterilized tools.

2 Repot the plant into a well-draining medium and incorporate perlite or horticultural grit to improve aeration and prevent future waterlogging.

3 Apply a fungicide to combat the Phytophthora pathogen and ensure the plant is in a container with excellent drainage, such as a pot with a drainage tray.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

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Nitrogen Deficiency

A lack of available nitrogen in the soil can cause an overall uniform yellowing of older leaves as the plant redistributes nutrients to newer growth.

Common

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How to confirm: Observe if the yellowing started on older, lower leaves and is spreading upward across the entire leaf surface.

build How to fix it

shopping_cart Recommended Products

1 Apply a nitrogen-rich organic fertilizer to the soil to replenish essential nutrients and promote green foliage regrowth.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

$30

In Stock

2 Incorporate organic matter like worm castings into the top layer of soil to improve long-term nutrient availability and soil health.

Back to the Roots Organic Worm Castings 5lb

Worm Castings

$17

In Stock

3 Monitor soil moisture levels using a moisture meter to ensure the plant is not experiencing water stress, which can mimic nutrient deficiency symptoms.