Why Are My Hostas Turning Yellow?

Hostas, also called plantain lily, has beautiful foliage with ivory, gold, blue and green shades. Therefore, the hostas plant is a favorite for most gardeners because of its beauty and easy maintenance. But when the leaves begin turning yellow, be sure something is troubling your plants, and you should address it.

Hostas leaves are turning yellow because the growing season has come to its close. The plant enters dormancy, preparing for winter, and it’s not a cause for alarm. However, if it turns yellow outside this period, it could indicate pest attack, disease, incorrect growing conditions, or hosta scorch.

This article will explain further why your hosta plants turn yellow and give you practical tips for caring for your plants. Read on.

Table of Contents

Is it Normal for Hostas’ Leaves To Turn Yellow?

It is usual for your hosta’s leaves to turn yellow at the end of the growing season, but if your plant yellows outside of the dormancy period, it may be a cause for concern. These factors include improper watering, nutrition, soil conditions, and external factors such as sun scorch or pests.

Lack of sunlight and accessible soil water during winter causes the plants to experience moisture stress, so most plants enter dormancy. The result is a lack of chlorophyll, causing the leaves to turn yellow.

However, It’s essential to differentiate the yellowing at the end of the growing season from yellowing due to other factors (which I’ll discuss below).

Your Hosta Is Yellowing Due to Moisture Stress

Overwatering and underwatering can also cause the hostas’ leaves to turn yellow. And they’re the easiest to remedy.

Andrew Gaumond, a botanist and Content Director at the Petal Republic, says that insufficient water in the soil makes it difficult for plants to accumulate the nutrients necessary for photosynthesis. The result is a loss of chlorophyll causing plants to turn yellow.

How To Know You’re Underwatering Your Hostas

Touch a few inches on the topsoil to check for mixture content. If the soil is bone dry, it’s time to water your hosta plants. According to Katie Williams, under-watered plants will look dry, with the leaves yellowing and crispy over time.

Hostas Plants Watering Schedule

It would help if you were careful not to drown your plants. Young hostas plants require daily watering for a fortnight. After this time, they’ll have developed into medium plants, and you can reduce the watering to once a week.

Hostas thrive in moist, well-drained soils and are tolerant to drought conditions. However, you can adjust the watering to thrice a week if it becomes hotter than usual.

Larger hostas plants require watering twice a week when it’s hot. However, potted hostas plants require even more watering. Pots drain quicker than gardens, so giving the plants the much-needed slow drink can become tricky. Slowly water potted hostas plants every three days during summer, and daily if the soil feels too dry.

When To Water Your Hosta Plants

Watering hostas plants early in the morning is ideal for giving them time to take up the moisture. 99% of indoor or outdoor plants need watering during the day. Ideally, most plants don’t need watering at night.

So it would help if you don’t water your hostas plants in the evening. They won’t take up much water, and the excess moisture might be ideal for harboring slugs and pests that can destroy the plants.

Water your plants regularly during summer and occasionally in the fall. Hostas are dormant during winter, so they don’t need water, particularly if exposed to snowfall.

Your Hosta Has Improper Soil Conditions

Hostas will turn yellow if the soil conditions aren’t right. Although they tolerate various soil conditions and would take terrible soil to upset them, they need well-drained soils.

Adequate drainage gives them room to breathe and take nutrients from the soil. Therefore, clay soils are out of the list. Clay soils remain wet for too long and cause waterlogging. Too much soil water causes yellow leaves.

You can add some sand or gravel to your local soil to improve it if it’s not well-drained.

Hostas plants thrive in slightly acidic soils. A pH of about 6.5-7.0 is good enough. You wouldn’t know the pH of your soil by looking at it. You’ll need a soil pH meter. It may seem too much for garden plants, but don’t you want your home to look fabulous?

You can buy Kensizer Soil Moisture/pH Meter (available on Amazon.com). It tests solid pH and moisture, so you won’t need to buy a soil hygrometer.

You can add cottonseed meal or peat moss to lower the pH for soils with a pH of more than 7.0. Add agricultural limiting agents for soils that are too acidic.

Your Hosta Is Yellowing Due to a Lack of Nutrition

Hostas plants are likely to turn yellow if proper nutrition is lacking. Nutrient deficiency is a sign if your hostas plant’s leaves turn yellow and the veins remain green. And it would help if you were fast to make things right.

Fertilizers and organic matter can give your plants the nutrients boost they need to stay healthy. A slow-release NPK 10-10-10 fertilizer would be appropriate to feed hostas plants.

Loamy soils are rich with organic matter and may not need much boost. You can add compost or mulch to give better results. But how would you know that the plants have exhausted the soil nutrients and need a boost with fertilizer? Do you wait until their leaves turn yellow? It’s simple; try a soil nutrients testing kit.

You Planted Your Hostas in Incorrect Temperatures

According to the National Gardening Association, hostas plants are hardy perennials growing in the US hardiness zones 3 to 9. Therefore, they tolerate various weather conditions and can do well in Minnesota, Montana, and Wyoming.

But your hostas plants may turn yellow due to extremely high or cold temperatures. Again, it’s not a cause for alarm.

Either way, most plants turn yellow when exposed to extreme temperatures. But if you’re worried about your beautiful plants turning yellow, maybe you can provide them with some shade. And while keeping them indoors, ensure the spot you place them isn’t too cold or too hot.

Heat is a common problem for gardeners who grow hostas which we will discuss below.

Hosta Plants Leaves Turn Yellow Because of Scorch

Hostas plants love partially shaded environments, and you will likely find them in shade gardens. If you grow them in direct sun, their leaves might turn yellow, especially if the sunlight is too much.

You’ll also notice scorches at the leaves’ margins. Hosta leaves turning yellow due to too much sunlight is called hosta scorch.

Transplanting garden plants or relocating potted ones is the best way to protect them from hosta scorch.

Your Hosta Is Yellowing Due to Diseases

Hostas turning yellow might indicate a disease has infected them. And knowing which condition is troubling your plant is as tricky as treating the disease.

Hosta Fungal Diseases

Crown rot and petiole rot are the common fungi that trouble hostas plants. Petiole rot sets in after warm and wet weather and manifests by yellowing the outer leaf parts. Fungal infections are difficult to treat and can kill your plants.

Hosta Bacterial Diseases

Dividing or pruning with contaminated tools is the leading cause of bacterial infection in hostas plants. They are affected more by bacterial soft rot. It sets in after harsh winters after the snow has damaged the plants.

The bacteria secrete enzymes on the plant tissues, causing them to become wet, soft, and smell like dead fish. The leaves develop yellow spots, and the plant withers and dies if the petioles are affected.

Viral Hosta Diseases

Insects and vegetative propagation contribute significantly to the transmission of viral infections. Tobacco rattle virus, hosta virus x, and Arabis mosaic are among the many viruses that affect hostas plants, causing yellowing and discoloration of the leaves.

The best way to prevent viral infections is to inspect new plants before introducing them to your garden. You also need to keep your garden free of weeds because they harbor viruses and pests that can transmit infections. Also, spray insecticides to eliminate virus-spreading insects from the garden.

Other Issues That May Cause Your Hostas Leaves to Yellow

If you have closely monitored your plant to ascertain the cause of your yellow leaves, and none of the above factors seem to be the issue, you should look for other reasons. Here are two main culprits that don’t fall into the above-mentioned problems.

Acclimation Issues That Cause Yellowing of Leaves

You might see your new plant’s leaves turning yellow and drooping if you bought it at a store instead of growing it from a seed. The plant’s roots might be taking time to adapt to the new environment, causing it to be slightly shocked by its new environment.

The hostas appearance might worry you, but it should go away in a few days. It’s a case of acclimation.

Hosta Pests

Worms and foliar nematodes living inside your hosta’s plants’ leaves might cause the yellow discoloration you see on the leaves in early summer. Brown streaks eventually appear between leaf veins.

Pune the affected twigs and leaves to prevent these pests from spreading to healthy plants.

Final Thoughts

Maintaining a garden and indoor plants requires a keen eye. You need to know when your plants need watering and when the water becomes too much. Knowing the reason why their leaves change colors solves the problem halfway if any.

Surprisingly, sometimes, when your hostas plants’ leaves turn yellow, you need to do nothing. The plants are adjusting to their new environment or the prevailing weather conditions.