Wisteria dies due to root rot if the plant is overwatered. A severe infestation of scale pests/Borer insects can also kill Wisteria trees. Sudden death of Wisteria is due to Honey fungal infection.
Wisteria is a genus of woody bines that look wonderful with their colorful blossoms. Wisteria is grown passionately in the eastern US.
Wisteria looks beautiful but it too can run into problems. One needs to take good care of the plant to see those pretty blossoms.
Wisteria leaves turning brown
Overwatering leads to browning leaves in Wisteria. Waterlogged conditions cause leaf yellowing first, these yellow leaves turn brown eventually. Canker diseases cause leaf browning in Wisteria too. Transplant shock can cause leaf browning in Wisteria too.
Wisteria doesn’t like to be overwatered. Water your Wisteria consciously. Make sure Wisteria is in a soil that has good drainage.
Soil with poor drainage also causes waterlogged conditions. You can add compost to the soil to fix drainage issues.
When you plant your Wisteria make sure it is planted in the high ground. The last thing you want is puddles around your Wisteria when it rains.
Check the soil with your fingers whenever needed and water your Wisteria only when it is dry up to 2 inches. Test the soil with a moisture meter if possible.
Wisteria root rot
Waterlogged conditions often lead to root rot in Wisteria. Root rot is a fungal disease which is not that common in Wisteria.
You can revive a root rotten Wisteria by reducing the amount of water you give the plant.
Canker diseases in Wisteria are caused by a variety of fungi. Cankers are either outgrowths or sunken lesions on the trunk of the tree.
These can form on the branches or the main stem of your Wisteria. Canker diseases kill the leaves of the plant, turning them brown.
The bark splits between the healthy and the diseased parts of the stem. This obstructs the flow of minerals and nutrients to the leaves, killing them.
Nectria canker is the common canker disease in Wisteria. Light and dark fruiting bodies are seen all over the infected branches/stem.
Treating canker in Wisteria
There is no way to treat canker in Wisteria once it infects the main stem. One can prevent this disease by keeping their tree healthy.
You need to prune out the diseased stems as soon as you see them. Try not injure your Wisteria unnecessarily as the fungus enters the plant via wounds.
Tip: Do not prune when the branches are wet to avoid spreading the fungus.
Contact a local arborist if you want to remove the canker without harming your Wisteria.
Wisteria can get affected by transplant shock if you are careless. The plant’s leaves turn brown when the plant is undergoing a transplant shock.
Water your plant abundantly immediately after transplanting to avoid transplant shock. Try to keep the root ball moist.
Add some sugar to water and make a solution. Adding this solution to the soil around the plant helps the plant in overcoming transplant shock.
Give your Wisteria some time to overcome transplant shock, do not try to rush things.
Wisteria leaves turning yellow
Wisteria leaves turn yellow due to overwatering/poorly draining soil. Wisteria leaves also turn yellow when the plant is given less water than needed. Wisteria leaves turn yellow also due to imbalance in the soil nutrients.
Although the primary symptom is same in all these cases you can find the cause if you observe the plant. Let’s see how!
Leaves of Wisteria turn yellow if it had more water than needed. Overwatered Wisteria leaves are not only yellow but are also limp.
Leaves of such overwatered Wisteria turn brown eventually. You need to check the soil with your fingers before watering the plant.
Underwatering can cause yellowing in the leaves of Wisteria too. Leaves turn yellow but are dry to touch due to the lack of water.
Underwatering stresses out your Wisteria. You’ll see that the leaves are falling off the plant. You need to respond quickly if you see these symptoms.
Water your plant regularly while making sure the soil has good drainage. Mulch the area around your Wisteria with bark chips and tree company chips to retain water better.
Wisteria Vein Mosaic Virus
Leaves of the Wisteria plant infected by this virus become wrinkled. Infected plant’s leaf veins turn yellow along with the areas around the veins.
This whitening or yellowing of the leaves can’t be treated. It is hard to get rid of the virus once it infects a plant.
The virus apart from discoloring the leaves doesn’t harm your Wisteria much. Wisteria Vein Mosaic virus doesn’t reduce the vigor of your Wisteria.
Wisteria leaves curling and yellowing
Aphid infestation is the reason why Wisteria leaves get curled and turn yellow in color.
Aphids are tiny insects which can fly and damage the plant by sucking out the plant sap via leaves. Their feeding habit causes the leaves to turn yellow in Wisteria.
Aphids if present in small numbers do not pose any threat to your Wisteria. If there’s a large aphid infestation then the plant’s health will deteriorate.
Small populations of aphids can be eliminated by the use of a water hose. You can also get rid of them by spraying the affected areas with Neem oil.
I don’t usually encourage spraying plants with insecticides. But if the infestation is large, feel free to do so.
Tip: Aphid infection can be confirmed early on if you notice honeydew on the plant.
Scale on Wisteria
Scale pests appear as bumps on the stem/branches of Wisteria. Scale attach themselves to the victim plant and suck the plant sap.
Their feeding habits cause the leaves to turn yellow in Wisteria. Prune off the infected parts of the plant if you catch the infestation early.
You can deal with small infestations by rubbing them with cotton swab dipped in rubbing alcohol.
A large infestation of scale can be dealt with by spraying the plant with Neem oil. In the late spring season spray the infected plant with horticulture oil.
Potted Wisteria leaves turning yellow
Overwatering is probably the main reason why potted Wisteria leaves turn yellow. Make sure the pot in which Wisteria grows has good drainage.
Check the soil and see if it’s too moist. If this is not the case according to you then the plant is root-bound. Move the plant into a bigger pot.
Why my Wisteria suddenly died?
Wisteria sudden death is most probably due to Honey fungus. Wisteria may also die suddenly due to the Phytophthora root rot disease. Prolonged waterlogged conditions can also kill the plant abruptly.
Wisteria is highly susceptible to a Honey fungus infection. The disease gets its name because of the toadstools it produces in the autumn, which are honey-colored.
Younger plants/shrubs infected by the Honey fungus die suddenly. Older, established trees can survive a couple of years before dying.
Sadly the tell-tale symptoms of this fungal infection don’t appear until it’s too late. Other symptoms include white growths under the bark and boot lace-like threads in the soil.
The infected plant dies back. If you peel the bark you can see these fan-shaped white outgrowths. These white outgrowths can be peeled off.
To fix Honey fungus
There’s now fungicide that can cure infected plants. The only thing you can do is to prevent the disease from spreading to other plants.
Uproot the infected plant if possible. If you can’t do this then try to build a barrier around the roots of the plant using a vertical sheet of heavy-duty polythene or PVC.
Phytophthora root rot in Wisteria
Phytophthora root rot in Wisteria is seen when the plant has been in waterlogged conditions for a long time. Overwatering or poorly draining soil can be the primary cause.
Phytophthora root rot if left unattended for a long while can kill your Wisteria. Increase the soil drainage by adding compost to it.
You need to be conscious when watering your Wisteria. Check the soil with fingers if needed. Water the plant only when the top two inches of the soil feels dry.
Wisteria Powdery Mildew
Powdery mildew is a common disease of Wisteria plants. The infected plant’s leaves get coated with a white powder as the name of the disease states.
Powdery mildew is a fungal disease which is favored by the moist leaves. Initially the leaves have yellow spots but eventually the entire leaves get covered in a powdery layer.
How do you treat wisteria with powdery mildew?
If left unattended such leaf spots turn brown or get perforated. You can prevent and control the spread by following good cultural practices.
Prune your Wisteria hard to increase the air flow. After cutting back the canopy if you still see the infection, spray Neem oil on the tree.
Wisteria leaf spot
Wisteria leaf spot is a fungal disease that is characterized by the formation of spots on the leaves. Infected plant’s leaves have small, yellow leaf spots.
These yellow leaf spots eventually brown and the leaves develop a ‘shot hole’ appearance. Do not wet the leaves of your Wisteria if you wish to prevent this disease.
Good air circulation around Wisteria is important to prevent fungal diseases. If the infection is severe, spray the plant with a solution of Baking soda in water(1/2 tsp. in a gallon of water).
Wisteria leaf scorch
Leaf scorch in Wisteria is usually seen in the summer when the tree can’t take too much sun. Leaf scorch is favored by drought conditions.
You need not panic when you notice leaf scorch on your Wisteria plant. The plant can take it and will revive itself in a couple of months.
If it’s summer just water the plant enough and see it bounce back. Add a layer of organic mulch to prevent unnecessary water evaporation.
An insect pest called Long-horned borer/Woodboring beetle is the primary reason for trunk rot in Wisteria. These borers drill holes in the trunk of Wisteria.
Borer insects drill holes in the trunk, then the females rest there and lay eggs. These pesky pests munch on the stem of the plant making it weak.
They eat away even vascular tissues. This causes great damage to the victim plant as it won’t be able to transport water and nutrients to the other parts of the plant.
To control/prevent Borer infestation
- Keep your Wisteria healthy so it can withstand Borer infestation to some extent.
- Remove the infected bines from your garden as soon as possible to prevent a large-scale infestation.
- Drop some petroleum based product into the holes of the borers. Petroleum based products suffocate the Borers.
- If all else fails, spray the young borers with Bacillus thuringiensis or Spinosad.
Happy Gardening 🙂