Common Hydrangea Diseases: Tips On Treating A Sick Hydrangea

Hydrangeas are one of the most popular houseplants in the world. They have been used since ancient times as decorations and they were even used as medicine during the time of Hippocrates (460 BC).

Today, hydrangeas are very common plants found all over the world. There are many varieties of hydrangeas with different colors and shapes. Some of them are commonly known as “blue” or “green”.

There are several types of hydrangeas, but they all share certain characteristics. Most of these characteristics include their shape, size, color and the way they grow.

All hydrangeas have three main parts; leaves, flowers and roots. Leaves are usually the largest part of any plant and they produce food for other parts of the plant such as seeds or water. Flowers are small structures that give off light and scent. Roots are the most important part of a hydrangea because they provide nutrients to the rest of the plant.

The following list contains some common hydrangea diseases and symptoms:

1) Leaf Curl – Symptoms Of Hydrangea Leaf Curl:

Leaf curl is a symptom caused by various factors. One of them is poor watering which causes dehydration in the plant.

The other reasons for leaf curl are: mechanical damage, dry air and frost. Also, leaf curl can be caused by viruses and bacteria.

There are several types of leaf curl and they all affect the leaves in different ways. The most common types of leaf curl are:

Damping off – The younger leaves are the first ones to show this sign. They turn downwards and start curling up before eventually dying.

This disease is usually caused by too much water and poor quality soil.

Curly Top – This disease starts at the top and moves its way down the plant. Young leaves are yellow and curly and as the disease continues, older leaves start dying as well.

Stripe – The most distinguishable part of this disease is the green and white stripes on the leaves. This disease usually targets only a few leaves but it can also spread to other plants too.

Common Hydrangea Diseases : Tips On Treating A Sick Hydrangea - Picture

In rare cases, blue or purple spots can be seen on the leaves.

2) Flower & Leaf Drop – Symptoms Of Hydrangea Flower & Leaf Drop:

This disease is fairly common but it can be cured easily. It causes the leaves and flowers to drop before reaching full maturity which results in a lot of brown spots on the floor.

This disease can be caused by several things such as insects, poor soil, or even irregular watering.

3) Common Hydrangea Viruses – Symptoms Of Common Hydrangea Viruses:

There are several types of viruses that affect hydrangeas. They can be transmitted through tools, soil and even human contact.

It’s fairly easy to get rid of these viruses but it requires a lot of attention. Most hydrangeas recover from these viruses but their growth is usually stunted and weak.

4) Root Rot – Symptoms Of Root Rot:

This is one of the most common hydrangea diseases and it causes the entire plant to die. It usually starts from the bottom and makes its way up.

The soil literally turns into mud and it smells terrible. It can be caused by several things such as: over watering, underwatering, poor drainage or even standing water. These causes usually occur when a gardener is inexperienced.

5) Common Rust – Symptoms Of Common Rust:

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This disease is fairly easy to identify. The lower and older leaves start turning yellow which eventually starts spreading to the rest of the leaves.

If the rust is serious enough the whole plant can turn completely yellow and die. This disease affects most types of plants and it’s fairly easy to get rid of it. All you have to do is apply some fungicide to the plant and that should do it.

6) Downy Mildew – Symptoms Of Downy Mildew:

This disease occurs more commonly in damp, humid weather conditions. White spots start to develop on the leaves which gradually grow and spread until the whole leaf turns yellow and falls off.

It’s important to remove affected leaves as quickly as you can. You should also apply fungicide to stop the spread of this disease.

7) Viral Infection – Symptoms Of Viral Infection:

Viruses in general have a very similar appearance to diseases. The main way of telling them apart is if the whole plant starts to look unhealthy and stunted then it’s probably a virus.

It’s fairly difficult to get rid of viral infections but there are a few things you can do. You can try re-potting the plant or grafting it to see if that helps. There’s also medicines you can apply to the leaves but these usually don’t have much of an effect.

8) Root-knot Nematodes – Symptoms Of Root-knot Nematodes:

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These tiny creatures target the roots of your plant and that’s where they lay their eggs. The feeding of these nematodes weakens the roots which prevents the plant from getting enough nutrients.

This disease gradually makes its way up the plant until the top starts to look unhealthy. Over watering and poor drainage allows this disease to thrive. If you find yourself dealing with root-knot nematodes, there are a few things you can do.

You can try applying nematode medicine to the soil to get rid of them. You should also make sure you aren’t over or underwatering your plant.

It might also be a good idea to re-pot the plant.

9) Blossom End Rot – Symptoms Of Blossom End Rot:

This disease is fairly easy to spot due to the characteristic appearance of the leaves. The bottom part of the leaves turn black and decay.

This problem is usually due to a lack of calcium so you should try adding extra calcium to the soil. You can also apply a fertilizer rich in calcium.

Sources & references used in this article:

Inflorescence color manipulation in hydrangea forced in media containing coal bottom ash and mine soil by DS Pitchay, MD Sherratt, BC Bearce – HortScience, 1996 –

Developmental and Spatial Characterization of Flowering in Hydrangea Macrophylla (Thunb.) Ser by W Orozco-Obando – 2005 –

Herbal medicines for common ailments: a quick reference guide by RM Tshiteya – 2007 –

Do All Bugs Need Drugs?: Conventional and Herbal Treatments of Common Ailments by D Hodgson-Ruetz – 2011 –

The Effects of Slow-Release Aluminum Sulfate on Bloom Color of Hydrangea macrophylla by S Trattler – 2013 – North Atlantic Books

Developing an Expert System for Papaya Plant Disease Diagnosis by PJ Edziak – 2015 –

An ethnopharmacological survey of natural remedies used by the Chinese community in Mauritius by MM Abu-Saqer, SS Abu-Naser – 2019 –

ETIOLOGY OF FOLIAR DISEASES OF COMMON by MF Mahomoodally, LD Muthoorah – Asian Pacific journal of tropical …, 2014 – Elsevier



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