There are few things more beautifulthan succulent hydrangea bushes . Unfortunately , their ravisher can be sullied by a phone number of fungous and viral diseases ( and two bacterial disease ) .
However , there are measure you’re able to take to keep your beauteous shrubs from come victim to one of these diseases .
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The reddish lesions on the leaves are a sure sign of Botrytis Blight.
We will put in you to the major hydrangea diseases , so you experience what to look for and how to prevent and care for them .
What You Will Learn
Fungal Diseases
Botrytis Blight (Botrytis cinerea)
This fungus can sternly affect the efflorescence bud and even pop them before they open . In addition , infected heyday parts can fall on the leave and taint them .
The first symptom are water - soaked dapple on the blossom . However , these grow into cherry dark-brown lesion .
Botrytis is more potential to be a problem under nerveless and damp conditions , such as several days of nebulous , humid , and showery weather .
The reddish lesions on the leaves are a sure sign of Botrytis Blight.
you could take steps to try and forestall this infection . Keep the humidness low . Do n’t water late in the day , and only water supply at the root , so you do n’t get the flowers and parting wet .
If you could , keep honest air flow around your plant . Space them properly , and prune arm that are closely spaced . care for your pruning shear with whitener as you prune , so you do n’t unintentionally spread any disease .
Also off drained or damaged flowers and leaves to keep the fungus from gaining egress into the plant . clean house up junk around the plant life , so that Botrytis ca n’t live on the dead tissue paper .
If you have a persistent problem , you may ask to use fungicide . option admit iprodione , or thiophanate - methyl radical .
Leaf Spots (Cercospora species andPhyllosticta hydrangea)
Cercosporamanifests as circular purple or chocolate-brown spots on the bottom of the plant . As the lesions get larger , the leaves can turn xanthous and fall off the plant .
tearing without getting the leaves smashed will serve to prevent these disease . If your hydrangeas do get infected , you have several options , include compost tea leaf , hydrogen hydrogen peroxide , garlic oil colour , or fluid kelp .
you may also apply the antimycotic agent chlorothalonil or thiophanate - methyl .
Anthracnose (Colletotrichum gloeosporioides)
plant that have been intemperately fertilized are more likely to foreshorten this common fungal pathogen .
carry on rainy weather or heavy murk produces the condition that favour infection .
The fungus produces large browned spot on the leaves or flower that will become more lightly colored in the centers . One distinctive symptom is that smear by the veins develop at an angle .
you may also care for this disease with liquid kelp , garlic oil , atomic number 1 hydrogen peroxide , or compost Camellia sinensis .
say more about identifying and treat anthracnose on hydrangea here .
Powdery Mildew (Erysiphe polygoni)
Powdery mould manifestsas a ashen powdery substanceon the surface of the leaves . you’re able to see white-hot , cottony increase on the bottom of the leave-taking .
Left unbridled , the fungus can taint the newly developing bud and stunt their maturation .
Powdery mold is most likely to be a problem on hydrangeas when the days are warm and the Nox coolheaded .
you could prevent the disease by reducing humidity and increasing air circulation .
One room to control this disease is to apply a fungicide as soon as you describe it . Another pick is to practice neem .
Rust (Pucciniastrum hydrangea)
Like other rusts , hydrangea rust fungus needs two hosts to survive and does not kill either of them . This rust only infects thesmooth hydrangea , H. arborescens , and poison hemlock as its alternate host .
The first symptoms are orange pustules on the bum of the hydrangea leaves and yellow musca volitans on top .
This disease is hard to control , but you’re able to manage it by clean up infected leaves and debris that has fall to the ground around both hosts . slight inside the hydrangea making sure to disinfect your pruning shear .
If you bed that rust is likely to be a trouble , you could arise the cultivar ‘ Frosty , ’ which is resistant to this disease .
Bacterial Diseases
Bacterial Wilt (Ralstonia solanacearum)
This important bacterial disease first manifests as blight in the leaves and flower cluster . However , more severe plague can get both wilt and root rot .
Bacterial wilting occurs mainly in red-hot weather and heavy rain . There are no chemic choice to control this disease .
Bacterial Leaf Spot (Xanthomonas campestris)
The bacterium that stimulate this disease can enter the plant through lifelike opening night like stomata or through wound .
The first symptom are water - soaked spot . The spots darken and become angular in form . These spots become larger wound and can kill the leave .
If you have a susceptible plant , you may protect it with copper hydroxide ( Kocide ) .
Viral Diseases
Fifteen different virus afflict hydrangeas!Hydrangea macrophyllais the most susceptible .
Transmission can occur by knives , foliage contact , andinsects like aphids . In some cases , plant epenthetic nematodes can transmit the viruses .
Prevention is the key in these eccentric . Quickly remove infected plants and their parts . Sterilize your pruning shears before cutting the plant , and plant clean stock in soilless media to avoid the computer virus that are channel by roundworm in the dirt .
These three are the most common viral infections that you are potential to encounter :
Hydrangea Ringspot Virus
If your hydrangea has brown blot or pack on its leaves , there is a good chance that it is infect with hydrangea ringspot virus . Then the leafage of the plant will start out to be falsify and rolled , and the growth of the plant will be stunted .
aphid do not spread this disease . However , it circulate mechanically , so tools can transmit this virus . Sanitizing your pruning tools will serve to foreclose the cattle farm of this disease .
Unfortunately , if your hydrangea contract this disease , you will have to purge it . variety that are tolerant to this computer virus are uncommitted .
Hydrangea Mosaic Virus
Hydrangeas infect with this virus will have a pattern of xanthous mosaics on their leaf .
This is another virus that is not transmitted by aphids . However , once again , you may spread out the computer virus with your tools . So be certain and disinfect your pruning shear to avoid unknowingly spreading this virus .
Tomato Ringspot Virus
This virus causes the leafage to move around chickenhearted and become malformed , and the growth of the plant will be stunted .
nematode , not pruning peter , distribute this virus .
If you aregrowing your hydrangea in container , you’re able to avert love apple ringspot virus by using a soil mix that is free of nematodes .
Such Beautiful Plants and So Many Diseases
There are a number of different organisms that can infect hydrangea flora and sully their beauty .
However , you may take step to keep your plants from becoming taint :
And if you want to know more about growing hydrangea bushes , then check out some of our other guidessuch as :
© Ask the Experts , LLC . ALL RIGHTS RESERVED.See our TOSfor more details . Originally published August 31st , 2019 . Last updated May 19th , 2023 . Uncredited photos : Shutterstock .
About
Helga George , PhD
