White spots on hydrangea leaves are an issue that would take place if you leave the plant overwatered, neglected, sunburned, or with no nutrients. Some white spots are caused by bacteria, while others can be the result of insects or even living conditions.
But how first you must know why they are happening, and then the ways to fix them. Let’s dive right in and see what the most probable causes for white leaves on your hydrangea plant are and how to deal with them.
Most Common Causes For White Dots On Hydrangea Leaves
The most common causes for white dots on hydrangea leaves would be due to powdery mildew, root rot, or a case of bacterial and fungal leaf infestation. In addition, they would also be due to pests, or the wrong living conditions given.
– Powdery Mildew
Getting this one straight out there, mildew is going to be your number one suspect! This fungal disease is the most common plant ailment in the world. It can happen anytime, anywhere, and in any condition, but it just loves when the scene is humid and hot. Being a fungal disease it will enjoy stale conditions created by excess humidity and warmth to germinate its spores.
These microscopic spores will travel by wind and water droplets, settling on top of your leaves in clusters and forming a thin layer of white powdery substance that will just look gruesome on your leaves. This is the issue that most common hydrangea would go through, and it would change the feature due to the spots that would arise.
This fungal situation can be identified as a powdery white substance on your leaves, that will smudge and spread upon touch. This fungal disease often begins in the outer layers of plant canopies and travels down to the ground. Hydrangea is a bushy plant, so you should be able to spot this one fairly soon!
– Root Rot
This is a disease commonly connected to overwatering. Oftentimes, flowers and petals will turn pale, white, drop, and won’t respond to being watered — essentially letting you know that roots aren’t sending any nutrients or water from downstairs. Plants infected by rotting roots will most likely die.
This rot usually occurs when the soil has been soggy for too long, without any drying period, or due to drought stress! This is a fungal disease, whereby the fungus penetrates the soil and produces fine web-like mats near where the stem is entering into the soil.
This one is tough to identify at first glance, but the symptoms should be evident pretty fast. The plant will surely struggle and will begin to look stressed, apart from white and yellow discoloration signs, in addition to the white spots that they would have.
If you suspect rot in the roots, you have a short time on your hands, where you should quickly dig out part of your root ball and inspect it for any white patches or dark and spoiled roots. However, things can often go sideways and plants will react by leaves turning yellow, brown, or even developing white spots, and this would be because the roots have been damaged
– Bacterial and Fungal Leaf Infestation
One of the most destructive diseases that can befall your hydrangea is bacterial leaf spot. It’s causing a lot of leaf damage and causes leaves to develop white spots with black and brown centers, due to the spread. Ultimately, the leaves get overridden with these spots and fall off. The same thing goes with the fungal counterpart or Cercospora leaf spot!
In parallel to this, the fungal spot thrives in moist and wet conditions and uses air and water droplets to fall on leaves and germinate and penetrate them. Leaf spots will soon spread if the wet conditions persist and will take over entire plants in a matter of days. However, if the weather conditions soon change to dry and sunny, the disease should go away all by itself.
The fungal spot is a natural seasonal disease in some climates, this is because the weather would be more humid than regular, and fungi would grow. Especially if there have been left any water droplets on the leaves of the plant, and this is when they will find the moist medium the ideal one to thrive in; you will also see them develop and grow in number as the leaves get further dots showing.
If those white spots appear to be moving all around in a hurry, then you’re likely dealing with some sort of sap-sucking insects. Common small insects will include aphids, mealybugs, and scale, and when these grow, they would also develop and hatch eggs.
In short, they have commonly grown hydrangea pests that can cause your trees to die if given enough time and space to breed and multiply, starting by growing on the leaves and actively developing.
Small white insects all clinch together to form protective communities and will resemble irregular white smudges or bumps, which means that if you observe, you will see these white spots vividly on the foliage.
You will surely know there’s an infestation if you notice honeydew or resin presence as well. This is the sap that’s gone through insect bodies and is now outside the hydrangea bush and on the leaves.
– Wrong Living Conditions
Sometimes living conditions can leave your leaves to suffer and turn pale and white. If you don’t abide by any of the living and watering standards, hydrangea will rebel by wilting and showing signs of white and yellow leaves.
Sometimes, white spots can be caused by excess exposure to the sun, which will burn the leaves like paper and leave them black, white, and curled up! Nutrient deficiency can also be diagnosed by white spots, so if you haven’t added any fertilizer to the ground pay close attention.
Common Ways To Treat White Spots on Hydrangea
The common ways that you can treat white spots on hydrangea would be to apply some fungicide or try to repot it into a fresh pot with clean soil, and lastly, you can also spread insecticide solution on the plant.
– Apply Some Fungicide
While hydrangea isn’t immune to mildew, it’s good to know that this disease isn’t harmful to it. However, it can look unsightly so let’s see how to treat it. First off, remove any infected leaves and especially those that have huge smudges on them, and try to use some fungicide solution, which in this case you can use natural ones if you don’t want to use a chemical one.
This means that you can remove any other spots with some rubbing alcohol and water. Simply dip the cloth in a mix of soap water and rubbing alcohol and rub the leaves clean; this will be a great choice as a fungicide, that will be beneficial to your plant.
Although powdery mildew is common happening in large parts of the world, you can still work out a way to prevent it from occurring. In this case, you don’t want to use anything aggressive for this specific disease, and a simple horticultural oil will go a long way.
What you must do is only apply a basic water solution of neem oil onto leaves every other month, and you should be just fine, and you can also do the same task for bacterial spots as well.
Rot isn’t going to be so forgiving on you and as soon as you spot it’s time for some drastic measures. You should pot your plant in fresh soil or a new spot altogether since the old potting mix or soil will surely have a deadly fungus present.
Simply begin by digging out the entire plant and remove any rotten roots and get rid of all the soil still clinging to them. After this, wash your roots thoroughly and replant your plant in a new place; this way you are getting rid of any fungus.
If you see signs of improvement and your plant jumps back to life in a week or two, then you will see that you accomplished your task and your plant is healthy again.
– Spread Insecticide Solution
Dealing with aphids and other sap-sucking insects shouldn’t go with the use of hard chemical substances. If so, then it’s already too late. Instead, try to go with a more plant-friendly home remedy, which is free from different synthetic solutions.
As previously mentioned neem oil is an awesome product to fight these pests. You can try to dilute it with some water and spray heavily all around your hydrangea shrub. If you don’t have any neem oil, rubbing alcohol or any other horticultural oil will do. Lastly, baking soda can also be used, mixed with water, and applying it all over; this option would work as well.
After you’ve washed away, and hopefully drowned these nasty bugs from your leaves, you can go through the bush with some cloth dipped in rubbing alcohol and water mixture. This is just a step to make sure your leaves stay clean and pest free for the remainder of the growing season.
Hydrangeas are beautiful plants that won’t leave anybody cold. These beauties have their own set of enemies, and some can even bring them to the brink of destruction, so let’s go through what we’ve said:
- Close-up inspection is will benefit your maintenance and solution strategy as not all conditions will have the same remedy.
- Powdery mildew and pests aren’t that dangerous, and you can get rid of them with ease, but the rot is something that can leave you without your favorite plant.
- To prevent diseases on hydrangeas, you should provide great living conditions, and don’t forget to use fungicides and pesticides once or twice a year as a preventive measure.
- You can also change the pot and the soil of the plant so that it thrives again without any problems taking place.
The white spots on hydrangea leaves are highly treatable and even preventable. Now that you know how to handle those white spots on the leaves, your hydrangeas will continue creating that amazing light show in your garden.
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