Hydrangea macrophylla Magical Ouverture White Cottony Spots - Causes & Fixes

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Mealybugs

These small, soft-bodied insects secrete a white, waxy, cottony substance to protect themselves as they feed on the sap of the Hydrangea stems and leaf undersides. They often cluster in the crevices between the leaf petioles and the main stem.

Very Common

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How to confirm: Use a cotton swab dipped in rubbing alcohol to dab the white spots; if they dissolve and turn brown, it is likely mealybugs.

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1 Isolate the plant immediately to prevent the mealybugs from spreading to your other houseplants.

2 Treat the infestation by spraying the plant with an organic insecticide or neem oil to kill the insects and remove the waxy coating.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

3 Use a cotton swab dipped in isopropyl alcohol to manually remove visible white clusters from the stems and leaf crevices.

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Powdery Mildew

A fungal pathogen that appears as white, flour-like patches on the surface of the leaves. In humid conditions, this can spread rapidly across the 'Magical Ouverture' foliage, causing leaves to yellow and curl.

Very Common

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How to confirm: Check if the white spots look like a fine dust that can be rubbed off easily with your finger rather than distinct clumps.

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1 Apply an organic fungicide to the affected leaves to stop the spread of the fungal pathogen.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

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2 Prune and dispose of any heavily infected leaves to prevent spores from spreading to healthy foliage.

3 Improve air circulation around the plant and avoid overhead watering to reduce the humidity that fuels mildew growth.

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Cottony Scale

Certain types of scale insects produce thick, white, fleece-like coverings over their bodies. These pests suck nutrients from the Hydrangea, which can lead to stunted growth and leaf drop.

Common

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How to confirm: Look for small, bumpy protrusions under the white fluff that do not move when disturbed.

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1 Apply an organic insecticide spray to the plant to eliminate the scale insects and their white protective coverings.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Manually remove visible cottony clusters from stems and leaves using a cotton swab dipped in rubbing alcohol.

3 Monitor the plant's health and ensure it receives adequate nutrition to recover from the nutrient loss caused by the pests.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

$30

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Woolly Aphids

These aphids produce a white, waxy secretion that gives them a fuzzy appearance on new growth. They are particularly attracted to the tender, succulent stems of young Hydrangea blooms.

Common

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How to confirm: Inspect the new, soft growth at the tips of the branches for tiny insects moving within the white fuzz.

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shopping_cart Recommended Products

1 Apply an organic insecticide spray to the affected stems and new growth to eliminate the woolly aphids and their waxy secretions.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Carefully prune and dispose of heavily infested tender stems to prevent the aphids from spreading to healthy blooms.