Rhododendron austrinum Yellow Leaves - Causes & Fixes

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Iron Chlorosis due to High Soil pH

Rhododendron austrinum is an acid-loving species; if the soil pH rises above 6.0, iron becomes chemically unavailable to the plant, causing interveinal yellowing in new growth.

Very Common

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How to confirm: Check if the veins of the leaves remain green while the rest of the leaf tissue turns yellow.

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shopping_cart Recommended Products

1 Lower the soil pH by applying an acidifying amendment specifically formulated for acid-loving plants.

FoxFarm Happy Frog Acid Loving Plant Fertilizer

Organic

$22

In Stock

2 Apply a chelated iron supplement or acid-loving fertilizer to restore iron availability to the root zone.

FoxFarm Bush Doctor Cal Mag Liquid Supplement 1 Pint

0.5 L • 1 pcs • Organic

$22

In Stock

3 Monitor soil acidity levels regularly using a pH tester to ensure the environment remains below 6.0.

YAMRON 4-in-1 Digital Soil Tester

Water Meters

$33

In Stock

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Root Rot (Phytophthora)

Excessive soil moisture or poor drainage causes fungal pathogens to attack the root system, disrupting the plant's ability to transport nutrients and leading to general chlorosis.

Very Common

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How to confirm: Gently lift the edge of the root ball to see if the roots are dark brown and mushy instead of firm and white.

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1 Immediately reduce watering frequency and ensure the plant is in a well-draining environment to stop the spread of Phytophthora.

2 Repot the plant in a highly aerated, acidic medium and consider adding perlite to improve drainage and prevent future waterlogging.

3 Apply a fungicide treatment to protect the remaining healthy tissue from further fungal attack.

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 nitrogen in the soil prevents the formation of chlorophyll, typically manifesting as a uniform yellowing that starts with the older, lower leaves.

Common

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How to confirm: Observe if the yellowing is progressing from the oldest leaves upward toward the new growth.

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shopping_cart Recommended Products

1 Apply a nitrogen-rich organic fertilizer to boost chlorophyll production and green up the foliage.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

$30

In Stock

2 Amend the existing soil with a nitrogen-rich organic amendment like blood meal to provide long-term nutrient release.

Back to the Roots Blood Meal & Gypsum (4 Pack)

Organic Fertilizer

$40

Out of Stock

3 Ensure the plant is in acidic soil, as Rhododendrons require low pH to effectively uptake nitrogen.

FoxFarm Happy Frog Acid Loving Plant Fertilizer

Organic

$22

In Stock

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Drought Stress

Golden Azaleas have shallow root systems that are highly susceptible to drying out, which can cause leaves to lose chlorophyll and eventually turn yellow or brown.

Common

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How to confirm: Check the moisture level of the soil 2 inches below the surface during dry spells.

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1 Immediately check the soil moisture level at the root zone to confirm the extent of the drought stress.