Hosta Leaves Turning Yellow? Here’s 10 Common Reasons Why

Is your hosta's leaves turning yellow? Unfortunately, this is an all-too-common problem for many owners of these spectacular plants. The good news is there's a few common reasons it happens. In this article, we take a deeper look at why your hosta's leaves may be yellowing, and what to do about it.

Hosta in Garden With Yellow Leaves

Hosta plants are a gardener’s delight, regardless of skill level. They are a perennial favorite of many given their easy care. Hostas have many varieties, though one thing they all have in common is how striking their foliage is!

This is attributed to more than just the leaves’ shape and markings; most varieties are a gorgeous, green color, too. If you have hostas in your garden, it’s likely one of your favorite plants. The last thing you want is your beautiful, verdant hostas turning yellow. However, sometimes these things do happen. The question is: what now? How do you deal with this common issue that plagues so many hosta owners?

There are several different reasons for your hosta plant yellowing. While all these issues will have their own solutions, it’s important to figure out just what’s been plaguing your plant. In this article, you’ll find 10 of the most common reasons for your hostas’ turning yellow, as well as fixes to ensure that it doesn’t happen again. Let’s get dig in!

Temperature

Autumn Hosta Changing Color
If your plant is kept outdoors, turning yellow is natural in the autumn and winter.

The first reason your hosta plant may be turning yellow is due to seasonality and temperature. In the case of hostas, being tolerant to most different kinds of weather, you only really need to worry if the temperature turns extremely hot or cold. They are grown in USDA zones 3 through 9, for your reference.

Any plant is bound to turn yellow when it’s exposed to extreme heat or cold. While you don’t have to worry about this too much with hostas, it’s still worth mentioning.

If you’re worried about the temperatures hurting your beloved hostas, you should look into providing them with some form of protection, especially since they thrive best in the shade. It’s worth noting that plants like the Hosta and other plants with big leaves may show their yellow color more visibly. This is not something to be concerned about.

Keeping your hostas indoors, you’ll still need to make sure they’re in a comfortable spot that isn’t too warm or cold. However, it’s not a high priority to place them away from vents where cold air blows in.

The growing season for hostas ends when the temperatures dip below 50 degrees Fahrenheit. You should expect to see yellowing at this time. When they go dormant, hostas can actually benefit from colder temperatures. Freezing temperatures present while the plant is dormant can help make for better, earlier emergence when the weather eventually turns warmer.

Improper Sunlight

Plant With Too Much Sunlight Exposure
Plants with too much sun can turn yellow, and crispy.

As we’ve previously mentioned, most hostas thrive best in the shade. You should note that their sunlight needs will depend on the cultivar. The rule of thumb is that they will need more sun if their foliage is lighter in color.

Varieties like the blue hosta, will need less. Regardless, all hostas will need some kind of shade, and will not benefit from being placed in very bright, direct sunlight. If you have a deeper green hosta, they will most likely benefit most from plenty of shade.

Placing a plant in a place that gets too much sun can cause the leaves to turn yellow, and eventually brown as they burn up from the exposure. Hostas are certainly no exception, so if you’re examining why your plant is turning yellow, you should determine the amount of sunlight they’re getting.

You can see this if the tips of the leaves turn yellow or brown, if the color of the foliage is fading, or if the color dulls in any way. If it’s too much, you should consider relocating your plant, whether it’s planted outdoors or indoors.

Note that dappled sunlight can be really good for hostas, especially those that are variegated. Sunlight is still necessary for photosynthesis, which is how plants create their food and stay nourished.

The key is striking a good balance between sun and shade, leaning mostly towards shade for these plants. Relocating your plants that are getting too much sun can most certainly have them turning green again sooner than you think.

Improper Watering

Overwatered Plant
Both over and under-watering your plant can cause problems, including nutrient deficiencies.

Improper watering can really create problems for your hosta, with it turning yellow in many cases. In all cases, both under-watering and over-watering a plant can be a recipe for disaster. Yellowness will often take hold over the leaves in spots, before spreading through the whole leaf.

Under-watering a plant will render it unable to take in nutrients, as water is the medium necessary for the transportation of nutrients through the plant. Over-watering is similar in that nutrients cannot be absorbed either, but this is because the plant is drowning, and thus suffocating.

You might be wondering how to tell if your plant is over or under-watered, given that the results are the same. An easy way to tell is by touching the soil. Insert one of your fingers into the soil, going a few inches deep. This is a good way to tell soil moisture, so do this before you plan on watering your hosta.

If the soil is clearly too dry, then it needs a good drink as soon as possible. If you have your hosta planted in a container, like a pot, it may be a good idea to place a dish underneath the pot to help catch excess water. This will help the roots drink in more water.

If the soil is still wet when you test it, then it shouldn’t be an issue to leave it be for a few days. Generally, you should allow the soil to dry out a bit before coming back to refresh it. Hostas like moist soil that isn’t too wet.

They are also good about a little drought when they’ve come to be well-established. However, take care not to leave them for too long just because they are hardy. Giving them deeper waterings every now and again is better than shallow watering more frequently. If you are growing your hosta indoors, stick to a schedule to help maintain the soil’s moisture.

Improper Soil Conditions

Planting Hosta with Gardening Soil
Hostas should have good, balanced soil, but can usually withstand many soil types.

A hosta can turn yellow from bad soil conditions. With that being said, it takes some pretty terrible soil to make a hosta upset. They are tolerant of many different kinds of soil, provided that it has good drainage.

Well-draining soil doesn’t retain excess moisture, allowing your plant the room it needs to breathe. Clay soils are bad for hostas because they stay wet for too long. Adding sand or small gravel to the soil may be necessary if your soil does not drain very well.

For best results, give your hosta soil that is slightly acidic. A good pH is somewhere around 6.5 to 7.0. Higher pH soils will need organic matter like peat moss or cottonseed meal to lower the pH. Soils that are too acidic can benefit from the addition of agricultural liming agents. Determine soil pH with a test kit, and adjust accordingly. Adding these to the soil can also improve drainage, as it raises the bed.

Most plants will be thrilled to live in soil rich with organic matter. Loamy soil may not need the addition, so if the soil is like this where you live, that’s fantastic! Fertilizer, compost, and mulch can really make a big difference for your hosta’s health and happiness. While we are on the topic of fertilizing…

Lack of Nutrition

Malnourished Plant
Leaves that are malnourished can often start to yellow and decay.

As we’ve previously covered, it isn’t always so simple to keep your plant’s nutrition in check. Improper sunlight, watering, and soil conditions can all make getting nutrition more difficult for your hosta. When nutrition is lacking, leaves are bound to turn yellow.

Nutrient deficiency can sometimes be seen if the leaves are yellow, but the veins are green. You may also notice your plant’s top leaves yellowing first. If you see this in your hosta plant, then you should work on making things right immediately.

Fertilizer and other organic matter can give your plant the nutrient boost it needs to stay healthy. This is especially true if you’ve planted your hosta in poor soils.

Determine what nutrients your plant’s soil is lacking by using a test kit. Then, purchase plant food that will balance out the nutrients. This should adequately address the issues with the soil, and thus restore your hosta to good health.

Bear in mind that when using any kind of fertilizer, you should follow the package’s directions thoroughly. Adding less than the recommended amount may produce little to no effect, which would certainly be a waste of time, effort, and resources. On the other hand, adding too much fertilizer can burn your plant, which could also be a cause for the leaves yellowing!

Fertilize hostas in the springtime, and in the summertime too if you deem it necessary. Ensure that granular fertilizers do not come in contact with the leaves. If growing your hosta indoors, it may be necessary to fertilize more frequently.

More frequent watering can mean stripping the soil of nutrients. Potted hostas will need slow-release fertilizer at the beginning of the growing season. As the growing season progresses, feed them twice a month with a water-soluble fertilizer. Stop the feeding process four months before they go dormant in the winter.

Root Damage

Plant with Root Damage
Damage to a plant’s roots can also cause problems, especially during planting.

Root damage can be a contributing factor to a hosta’s yellowing. Compacted roots in particular can be highly damaging to your plant. This occurs when the plant outgrows the space it has been planted in, especially if it is in a container. The roots will become compacted and damaged, and then the leaves will begin to yellow before eventually falling off.

Pruning the roots by gently lifting the plant out of where it is planted can make a difference. However, in most cases, planting them somewhere they can spread more readily is the best solution.

When planting your hostas, whether in the ground or in a container, it’s important to leave them plenty of room for the roots to grow. This promotes the horizontal spread of the plant, and allows it enough room to breathe.

Planting holes for hostas should be dug around a foot deep. The hole should also be 1½ times as large as the projected mature size of your plant, to allow for adequate spread.

Aeration is highly important to the health of your plant’s roots. This can help prevent the roots from becoming compacted. Good drainage, again, is also necessary, as this allows roots ample space to grow. Addressing these needs can keep your hosta’s leaves green.

When replanting your hostas, take a close look at the roots; this is a good way to determine their health. Healthy roots are a pale, whitish yellow color. Diseased roots will be dark, often indicative of a rot, especially if there is a foul odor present. In this case, you will need to discard the plant and start over with a new one, as there’s no way to save it.

Bacterial Infection

Infected Plant with Yellow Leaves
Fungal infections can cause problems with yellowing and decay.

Bacterial infections can really take a toll on your hosta’s health. One bacterial infection in particular, known as bacterial soft rot, can manifest in the yellowing of your hosta’s leaves. You will also know it by a foul odor coming from the plant, denoting the decay of the lower leaves caused by the disease.

This disease is caused by several different types of bacteria, and frequently occurs where there has been a wound on your plant, caused from division or planting. Wounds can also occur if the winter has been particularly harsh, where the ground heaves and thaws (so be sure to give your dormant hostas enough protection for the winter!).

Unfortunately, you will need to destroy all infected plants to get the situation under control. Do not use your tools on healthy plants without having thoroughly cleaned them first. Moving forward, be careful not to excessively wound your hosta plants when separating them. This can prevent another outbreak.

Viral Infection

Plant with Viral Infection
Infections that are viral in nature, can cause yellowing and fraying of the leaves.

Viral infections are also quite nasty and can be devastating to your hosta plants. They are the cause of some cases of yellowing, among other negative effects. One virus that badly affects hostas is Hosta Virus X.

It can be difficult to detect this virus, as it is relatively unnoticeable and may stay that way for a few years. Eventually, you may see a yellow mosaic pattern forming on the leaves, the thinning of leaf tissue that ends up wrinkled, and variegated leaves may blur in pigment and lose the definition of their borders.

This disease is often spread when cutting plants. The infected sap of one plant often comes into contact with a healthy plant, thus contaminating it. In all cases, you will sadly have to destroy all plants that have the virus.

Never divide plants you know or suspect to be infected. Clean all your tools thoroughly before using on healthy plants. Mitigating the spread is key here. For further prevention, ensure to purchase plants only from reputable nurseries, as disease is less likely to come from these places.

Fungal Infection

Yellow Plant with Fungal Infection
A fungal infection can also cause a plant’s leaves to turn yellow.

One other reason for yellowing leaves on your hosta plant is fungal infection. While this can be difficult to treat, it often does not end in you needing to discard the whole plant. Despite that, you should still take care to treat the infection and contain it as soon as possible. Petiole rot, formerly known as hosta crown rot, is one such fungal disease that needs immediate attention.

You can spot petiole rot by observing the leaves turning yellow and brown around the margins. The petiole becomes soft and mushy; the leaves go limp. You will also be able to pull the leaves from the main plant without much effort.

In many cases, you will be able to see the mycelium of the fungus, which looks like white threads. This disease in particular releases spores that attach at the base of the petiole. The sclerotia, which is where the fungus stores its food, is usually inactive in cold weather, waking up with warm and humid weather.

Treatment for this condition can begin with containing the infection. Remove any infected tissue that you see and be careful to dispose of it properly. Fungicide can also be effective when used correctly.

Chlorothalonil, mancozeb, and iprodione are good choices. To prevent the spread of the fungus, do not transplant any hostas you know to be, or suspect may be infected. Avoid mulching around the base of the plant until the infection is eradicated. Lastly, moving forward, it’s a good idea to keep your plants cool to prevent the warm, moist conditions that fungi love.

Natural Adjustment

Planting a Seedling in Soil
Most plants that have been recently transplanted will take time to properly adjust.

The final reason your hosta plant may be turning yellow is simply because of natural adjustment. Before coming to this conclusion, ensure that you’ve ruled out any other possibilities, since the others are definitely important to look out for!

If you’ve gone through the list and determined that none of these are the issue, it could just be that your plant needs time to adjust. There are two things to keep in mind in the natural adjustment: acclimation and the natural life cycle.

Acclimation

Acclimation will be an issue if you’ve bought a plant from a store instead of growing it from seed. Whenever you purchase a new plant, they’re probably going to be at least a little shocked to be in a new environment. They were probably very comfortable in their greenhouse before they were picked up, transported to your home, and planted where you chose. As such, it’s only natural for them to be a little dramatic in their new home.

It could be that their leaves turn yellow, or the plant starts drooping, or lower leaves start to die. This can be alarming, but if it’s really just a simple case of acclimation, then it should right itself soon. A few weeks of you tending to your plant carefully should perk it right back up, and your hosta will be back to green in no time.

Natural Life Cycle

In the hosta’s natural perennial life cycle, it’s to be expected for it to eventually start yellowing and dropping leaves as it goes into dormancy for the winter. This is just the reality of herbaceous perennials, which your hosta plant is.

You can help it along the process by pruning back the yellow leaves, to help it prepare for its long winter sleep. Ensure that your plant is properly protected for the winter, and you should see it pop back up when the weather gets warmer.

Final Thoughts

We hope that this article has helped you understand why your hosta plant’s leaves are turning yellow. More importantly, we hope that the solutions we’ve provided have helped you set things right for your plant. While it takes some effort to bring your hosta back into the pink (or green!) of health, it’s all well worth it.

Applying these solutions could really make a world of difference much sooner than you think. Hostas are a hardy plant, and with the help of a green thumb, bringing your yellowing plant back to life may be easier than you’d initially thought!

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