The hydrangea is one of the robust garden plants that is rarely attacked by fungi. This is precisely why you should check the plant with its beautiful flowers regularly. In this way, fungal diseases can be detected and successfully combated in their early stages.
How to treat fungal infections on hydrangeas?
Hydrangeas can be affected by fungal infections such as powdery mildew, downy mildew, leaf spot and gray mold. To combat the infestation, affected parts of the plant should be removed, the hydrangea should be fertilized regularly and treated with natural products such as garlic or onion decoction.
Common fungal diseases
The hydrangea is particularly affected by these fungi:
- Powdery and downy mildew
- Leaf spot disease
- Gray horse
Mildew fungi
Under certain weather conditions, mildew multiplies rapidly. Both powdery mildew and downy mildew can cause so much damage to the hydrangea that it even dies. This plant disease must therefore be combated early and consistently.
Powdery mildew
This mushroom is a typical fair-weather mushroom that spreads particularly in pleasantly warm and dry weather conditions.
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On the upper side of the leaves, and in cases of severe infestation also on the stems, buds and flowers of the hydrangea, a white, flour-like coating appears. The infected plant parts wilt and die.
Downy mildew
Unlike powdery mildew, downy mildew is a bad-weather fungus and requires a lot of moisture to grow. It can multiply rapidly, especially in rainy and cool summers.
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A whitish-gray fungal lawn becomes visible on the underside of the leaves. If the infestation is severe, brown, yellow or purple spots appear on the upper side of the leaves.
Fighting mildew
- Cut off affected plant parts and dispose of them in household waste. Under no circumstances should you add it to the compost, as the spores will spread throughout the garden when the fertilizer is applied.
- For powdery mildew, spray with agents containing neem or silica (€11.00 on Amazon), for downy mildew, spray with garlic or onion decoction.
- In the case of powdery mildew, spraying with milk supports the treatment.
Leaf spot disease
Poor nutrient supply and wet weather conditions promote the spread of this fungal disease.
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You can recognize the fungus by the brown spots with a very dark center. As the disease progresses, these areas thin out and tear.
Combat
- Remove affected plant parts and dispose of them in household waste.
- Fertilize hydrangeas regularly.
- If the fungal disease cannot be contained by these measures, treat with a fungicide.
Gray horse
If the humidity in the winter storage is too high or if there are wet weather conditions over a longer period of time, gray mold has an easy time of it.
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The young shoots, inflorescences and leaves show a dirty gray, powdery fungal growth. The plant parts wither away.
Combat
- Cut off affected plant parts.
- Always water the hydrangea in the morning so that splashed water can dry quickly.
- Tighten the hydrangea regularly to ensure good air circulation.
Tips & Tricks
As a preventive measure, spray the hydrangea with a broth made from field horsetail. This effectively prevents many fungal diseases.
