If you’ve ever let a Wisteria plant get a little out of control, you know that their growing ability is pretty incredible. There’s a reason that an established Wisteria is nearly impossible to remove. However, that doesn’t mean that these plants are entirely invincible. Sometimes they wilt and turn yellow or brown. So why does that happen?
Wisteria is a tough plant that will grow well in many different conditions. However, some of the most common causes for Wisteria problems include overwatering, pest damage, diseases, and environmental conditions. The good news is that most problems are preventable or treatable.
This article will discuss the issues affecting your Wisteria plant and what may be causing those problems. I’ll also give you some tips for dealing with the most common reasons for Wisteria dieback and tell you how to bring your plant back to life.
Did I Kill My Wisteria?
Wisteria is known for being a hardy plant that grows easily in a variety of conditions. In most cases, it’s pretty hard to kill. So, chances are that you did not kill your Wisteria! Wisteria is a deciduous plant, meaning that it loses its foliage each winter. They’re also prone to yellowing leaves, which could happen due to several reasons.
Wisteria is typically self-sufficient, but there are some cases where your plant’s condition may warrant your attention. Suppose you notice your Wisteria has severe yellowing or browning, drooping, wilting, a lack of blooms, or brown spots on your Wisteria’s leaves. In that case, you may need to do a little investigating to figure out the root cause of your Wisteria’s woes.
Problem: Wisteria Leaves are Turning Yellow or Brown
Wisteria naturally loses its leaves each winter, and they’ll typically turn yellow in the fall before they fall off completely. Some plants may start this process toward the end of summer, depending on when the temperature begins to change and where you live. However, if your Wisteria’s leaves are yellowing during the spring or early summer, it may be a sign of a deeper issue.
A few yellow leaves here and there are also expected, as the plant can change with the moisture and nutrients in the soil, but if all your leaves are turning, there’s probably something else going on.
Reason #1: Overwatering
One of the most common reasons for Wisteria to experience leaf discoloration is overwatering. Wisteria does not like soggy roots, so it’s important to plant it in soil that drains well. If you notice puddles around your Wisteria plant every time it rains, it may not have adequate drainage.
If you live in an area without much rain and have to water your Wisteria plant, make sure to do so with care. Always check the soil first, using your finger to feel whether the soil is moist or dry. Only water your Wisteria when the soil feels dry on the surface and just under the surface. For best results, use a soil meter to monitor the moisture level before watering.
Reason #2: Pests
Another problem causing leaf discoloration is the presence of pests. Aphids are tiny insects that feed on plant tissue, causing damage to the foliage. New growth is especially susceptible to aphid damage. When these tiny pests infest a plant, the leaves typically become deformed and turn yellow, eventually dying and falling off.
The best way to deal with aphids is to introduce natural predators like ladybugs into your garden. You can also hose them off your plants with a strong water stream, unless it’s a severe infestation. In that case, you may need to use something like insecticidal soap to control the insects.
Reason #3: Sun Damage
If you live in a hotter climate or the sun is really intense on your Wisteria plant, it can cause minor sun damage. This is even more likely if the plant isn’t getting enough water. If most of the leaves take on a pale yellow color (or light green) and look pale, they’re likely getting too much sun and becoming overheated.
If this is your issue, you can try to provide some shade for your Wisteria plant or increase its water intake until the temperatures start to cool down some. However, this is typically a temporary problem that resolves itself, so you shouldn’t have to worry about it too much.
Problem: Wisteria is Drooping or Wilting
A suddenly drooping Wisteria plant can be a concern for this vigorous vine. Many explanations could help you to understand why your Wisteria is starting to wilt, but most of them are common issues that are easily addressed. The most alarming problem is when drooping and wilting turns into dieback. Dieback is one of the most frustrating problems Wisteria growers may face, and it can be tricky to diagnose the precise reason.
Reason #1: Wisteria is Waterlogged
We’ve already discussed the dangers of overwatering, but it’s a prevalent cause of various problems with the plant. Wisteria really doesn’t like to sit in oversaturated soil, and if the plant becomes waterlogged, it can lead to root rot.
If you catch the problem early, you can reduce the amount of water you give your Wisteria going forward and hopefully save the plant. However, if the issue isn’t addressed, it may get to the point where the only hope is to dig up the Wisteria and trim away the diseased roots, then replant it in a dry location. If too much of the root system is damaged, the plant may not survive despite your best efforts.
Reason #2: Wisteria is Infected by Honey Fungus
Honey fungus is a severe fungal disease that can affect many different trees and shrubs, and Wisteria is no exception. If you notice white growth under the bark on your plant, sudden wilting and dieback, and honey-colored toadstools around the plant’s base, you may be dealing with honey fungus.
Unfortunately, this disease is almost always fatal for the plant. The best thing to do is dig up and dispose of the infected vine to keep the condition from spreading. However, you can help to prevent honey fungus by keeping your Wisteria plant thoroughly fed and watered. Honey fungus tends to prey on more susceptible plants, like those that are young, weak, or stressed. Keeping your Wisteria healthy will help keep it safe from honey fungus.
Problem: Wisteria is Losing its Leaves
There are many causes for your Wisteria to lose its leaves. Keep in mind that it’s normal and expected for it to lose all of its foliage each winter as it goes into a dormant state. If you find that your leaves are dropping outside of that period, you may have some other issue causing stress or damage to your plant
Reason #1: Insects and Pest Damage
When the leaves start disappearing or falling off from plants, one of the most common reasons is that something is eating the leaves. Several pests enjoy snacking on Wisteria, and any one of them could be the culprit. Here are some of the main pests to look for:
- Bean Aphids: Small, black, bean-shaped insects. Natural predators include parasitic wasps, lady beetles, soldier beetles, and syrphid beetles. Insecticidal soap or oil can control extreme cases.
- Armored Scales: These insects may look like a physical abnormality on your Wisteria, but their sticky excretions make them easier to identify. Parasitic wasps or horticultural oil can control these pests.
- Soft Scales: These insects are waxy, smooth, or cotton-like in appearance. They’re also very small – ¼ of an inch or less. Fight an infestation using the same methods as armored scales.
- Longhorn Beetle: These brightly colored beetles are easy to spot with their horn-like antennae. They also eat holes in the woody parts of the plant. These pests typically go after weakened plants or those that are already suffering from damage. The best defense against these beetles is to keep your Wisteria healthy with pruning and proper watering.
Reason #2: Heat Stress and Drought Stress
If your Wisteria isn’t getting enough water and conditions are too hot, leaves may become limp and fall off. Wisteria can live in hot climates if you give them enough water and protect the root system. Be sure to increase watering during hot, dry weather. Cover the soil with a layer of organic mulch to provide insulation and protection for the root system.
Problem: Brown Spots on My Wisteria’s Leaves
Brown spots on leaves are a fairly common problem across many plants and shrubs. However, it can be especially alarming on the lush, green foliage of your Wisteria plant. Irregularly shaped brown spots may indicate a number of potential issues, and most of them are not good. However, keep in mind that these problems are not especially common, so you don’t need to worry too much.
Reason #1: Wisteria has Powdery Mildew
If the blotches are dark brown and have a yellow margin, your plant may be infected with powdery mildew. This fungal disease will result in white fungal growth on the leaves that’s extremely difficult to see with the naked eye. The sign that most people notice is the presence of brown spots. Another symptom you may notice is a pale green or yellow area of disease on the leaves during early summer when the problem arises.
To control this issue, try to identify and prune away any infected foliage (especially during the fall) to help reduce the amount of impacted plant tissue during the following season. Don’t let your Wisteria get overly moist or over-fertilize. If natural measures don’t fix the problem, you can use an antifungal treatment to control the infection.
Putting it All Together
Wisteria is a hardy, vigorous grower that will bring you decades of dazzling blooms if the conditions are right and the plant stays healthy. One of Wisteria’s most appealing traits is how low maintenance it is to grow. However, that doesn’t mean that your plant won’t be affected by the same kinds of issues as most other shrubs and vines.
The most common problems for Wisteria are caused by just a handful of issues, such as overwatering, fungal infections or diseases, pest damage, or environmental conditions. If your Wisteria is suffering from one of the problems discussed in this article, start with the basics and work your way to more complicated issues. Always start with water and sunlight — ask yourself if your Wisteria is getting enough sunshine and check the moisture in the soil. This will solve most of your problems.
If you get the environment right, your Wisteria will come back to life in no time. Remember, patience is key when dealing with Wisteria. Nothing happens overnight with this plant, but you’ll be happy you gave it the time it needed when you smell the sweet aroma of its flowers each year.