Daylilies are stunning plants that add a vibrant splash of color to any garden. Seeing yellowing leaves in your daylily garden can be disheartening. So, what causes them to yellow?
Your daylily leaves are turning yellow due to the plant’s natural life cycle, extreme sunlight, over or underwatering, and nutrient deficiencies. A pest infestation, poor soil quality, too much shade, or fertilizing can also cause them to yellow.
Yellowing daylily leaves can signify many issues, but this doesn’t necessarily mean the end of your daylily garden. The rest of this article will discuss 11 potential causes of yellowing in daylilies so you can diagnose, manage, and hopefully treat such issues. Let’s get started!
11 Causes of Yellowing in Daylilies
Yellowing in daylilies can be due to one or several reasons.
Let’s take an in-depth look at these reasons and the steps you can take to prevent your plant’s leaves from turning yellow:
1. The Daylily’s Natural Life Cycle
Daylilies are perennial plants with a lifespan of around 2 years, and the natural yellowing of older leaves comes with age and the changing of seasons. The yellowing in older leaves is a normal part of the plant’s life cycle and can be easily distinguished from unhealthy yellowing.
Yellowing leaves, due to age, can be identified when the younger leaves remain green and healthy while the older ones closer to the ground start to turn yellow. If you see yellow daylily leaves throughout the plant, then it’s likely something else is causing the issue. Read on for other possible causes of yellow daylily leaves and how to treat them.
2. Overwatering
Many gardeners assume that if some water is good, more must be better. However, this isn’t always the case. Daylilies thrive in moist soil, but too much water can be just as damaging as underwatering.
Overwatering causes root and crown rot, which can lead to the yellowing of the leaves. If you think your daylilies may be overwatered, test the soil for moisture before providing more water.
A good rule of thumb is to check the soil before watering your daylilies. If the soil is dry 3 inches (7.62 cm) below the surface, it’s time to water it. If your daylilies are growing in constantly wet soil, it’s easy to get rid of the problem by simply allowing the soil to dry out between watering.
Daylilies only need about 1 inch (2.5 cm) of water per week, so take care that you’re not watering it too much. This should be enough to keep the plant healthy without causing any issues from overwatering.
You can also avoid overwatering by planting daylilies in raised beds or well-draining areas. This will make it easier to control the amount of water your plant receives. If your daylilies are planted in pots, make sure the pots have plenty of drainage holes so that excess water can escape more easily.
Remember that potted daylilies require more frequent watering than those planted in the ground, so check the soil moisture daily. If it’s still damp from your last watering, wait until it’s completely dry before providing more water.
3. Too Little Water
While over-watering can cause yellowing leaves, daylilies that don’t receive enough water can suffer from the same issue. Although these plants are fairly drought tolerant, they require regular watering to stay healthy. Without enough water, daylilies won’t be able to absorb the nutrients they need, leading to the yellowing of the leaves.
You can check if your daylilies are getting enough water by checking the soil moisture at least once a week. If the soil is dry 3 inches (7.62 cm) below the surface, it’s time to water your daylilies. You may need to water your plants more frequently if they’re planted in pots or sandy soil.
Providing daylilies with 1 inch (2.5 cm) of water per week should be enough to keep them healthy, but if you live in a hot, dry climate or your daylilies are planted in a spot that receives less natural rain, you may need to water them more often.
It’s best to water daylilies early in the morning when the temperature is cooler, and there’s less chance for evaporation. This will help ensure the plants get enough moisture.
Consider investing in a moisture meter if you need help determining how often to water your daylilies. These devices can help you monitor the soil moisture and ensure your daylilies get just the right amount of water.
Another alternative is setting up an irrigation system or drip hose to provide a consistent and even amount of water to your daylilies throughout the week. This can help save you time and energy and will ensure your daylilies are always receiving the moisture they need to keep them healthy.
4. Extreme Sunlight
You might be surprised to learn that too much sunlight can cause daylily leaves to turn yellow. Daylilies prefer dappled or partial shade rather than full sun. If you’re watering your daylilies appropriately and the leaves are still yellowing, check if they’ve been planted in an area that receives full sun.
If that’s the case, it’s easy to eliminate this problem by relocating them to an area with a bit more shade or providing some sort of sun protection, such as a light shade cloth. This should help protect the daylilies from the sun’s harsh rays and keep their leaves a healthy green.
These plants need at least 6 hours of indirect sunlight daily to thrive, so ensure you’re not planting them in an overly shady spot. Finding the right balance of light and shade is key to keeping your daylilies healthy, strong, and vibrant.
Remember that the amount of sunlight in your garden will change as the seasons progress. If you live in a temperate climate, your daylilies will receive less sunlight during the winter. It’s essential to keep the amount of sunlight your daylilies are receiving in mind as the seasons change to ensure they get the correct amount of light to keep them healthy.
5. Poor Soil Quality
Daylilies need nutrient-rich soil to thrive, and if the soil isn’t up to par, your daylilies won’t be either. Poor soil quality can lead to yellowing leaves, as the plants won’t receive the necessary nutrients.
The soil’s pH level is especially important for daylilies, as they prefer a pH between 6 and 6.5. If your soil falls outside of this range, your daylilies will struggle to absorb the necessary nutrients from the soil.
You can test the pH of your soil with a simple soil test kit. If the pH level is off, you can adjust it by adding compost or lime to the soil. You can also improve the quality of the soil by adding mulch or well-rotted manure.
These amendments can help improve the soil structure and make it easier for your daylilies to absorb the necessary nutrients. You can also fertilize your daylilies with a balanced fertilizer to give them the extra nutrients they need.
Be careful not to over-fertilize your daylilies, as this can lead to yellowing leaves, further exacerbating the problem. Use a gentle fertilizer and follow the instructions carefully to ensure your daylilies receive enough nutrients without getting too much.
6. Compact or Poorly-Draining Soil
Compact or poorly-draining soil can also cause yellowing leaves in daylilies, making it harder for the plants to absorb oxygen and water. If your soil is too compact, it can prevent air and water from reaching your daylilies’ roots.
This can lead to root rot, one of the leading causes of yellowing leaves in daylilies. You can add compost or well-rotted manure to your soil to remedy this issue. This will help improve the soil structure and make it easier for oxygen and water to get down to the roots.
Consider adding perlite or sand to your soil, which will help it drain better and provide more oxygen. If your soil is too sandy, you can add clay to help retain moisture and nutrients. However, mix the clay well, or it can create dry pockets that can harm your daylilies.
Additionally, you can improve drainage by planting your daylilies in raised beds or mounds. This will help reduce the possibility of root rot and should improve the overall health of your plants.
7. Sudden Temperature Changes
Daylilies are tropical plants and are very sensitive to extreme temperature changes. Although these plants are fairly resilient, they can easily be harmed by sudden swings in temperature, like those caused by surprise cold fronts or hot spells.
If the temperature drops too low, your daylilies may suffer from frost damage or freeze. This can cause the leaves to turn yellow and then die off completely. Similarly, if the temperature rises too high, your daylilies may suffer from heat stress, and their leaves may become yellow.
However, these issues are usually temporary, and if you act quickly to protect your daylily plants from future temperature fluctuations, the leaves should return to normal. Try to keep an eye on the weather and take steps to protect your plants if a cold snap or heat wave is imminent.
The best way to protect daylilies from extreme temperature changes is to choose a sunny, sheltered spot in your garden and mulch the soil around the daylilies. Additionally, you can erect lightweight row covers over the plants when sudden temperature drops are possible.
8. Too Much Shade
Daylilies need plenty of indirect sunlight to thrive and bloom. If your daylily plants are in too much shade, they may develop yellow leaves because they aren’t getting enough energy from the sun for photosynthesis.
Provide your daylilies with the correct amount of sunlight by planting them in a sunny spot and limiting the shade they get. If you have existing daylily plants that are getting too much shade, you can move them to a sunnier place.
However, be sure to keep in mind that daylilies don’t stand up well to transplanting. They may suffer from transplant shock, and their leaves may turn yellow. If you decide to move your daylilies, do it in the early spring. It’s best to wait until the cooler months of fall to transplant daylilies.
Another way to provide your daylilies with the proper sunlight is to prune nearby plants to increase air circulation and light exposure. This should help the daylily plants get enough sun without being transplanted.
If you plant them in pots, try to rotate them regularly so that all sides of the pot receive equal exposure to sunlight. This should improve their overall health and hopefully stop the leaves from yellowing.
Remember that the amount of sunlight in your garden will change throughout the year. If you’re in a temperate climate, your daylilies will receive less sunlight during the winter. Keep the amount of sunlight your daylilies are receiving in mind as the seasons change, and make adjustments accordingly.
9. Nutrient Deficiencies
Nutrients are essential for daylilies to grow and thrive; if they don’t get the necessary nutrients, their leaves can turn yellow. The most common nutrient deficiency is nitrogen, the primary nutrient needed for optimal plant growth.
A lack of nitrogen in the soil can cause the lower leaves on your daylilies to turn yellow and die, while the new leaf growth will be pale green. Other essential nutrients, like phosphorus and potassium, can also cause leaves to turn yellow if they’re not present in adequate amounts.
To ensure your daylilies get the nutrients they need, you should fertilize them regularly with a balanced fertilizer. These fertilizers typically contain all of the necessary nutrients in adequate amounts, so you can be sure your daylilies are getting what they need.
Additionally, adding organic matter, like compost or manure, can provide the necessary nutrients and help improve the soil structure. This will make it easier for your daylilies to access the nutrients they need and help prevent yellowing leaves.
10. Too Much Fertilizer
It’s easy to over-fertilize your daylilies. While adequate fertilizer is essential for optimal growth, too much can lead to yellowing leaves. Too much nitrogen in the soil will cause excessive leaf growth that can lead to nutrient deficiencies and yellow leaves. Salts and other chemicals in the fertilizer can also burn the plants and cause the leaves to turn yellow.
As such, you should always be careful when applying fertilizer to your plants and follow the instructions on the fertilizer package to use only the recommended amount.
If you suspect your daylilies are getting too much fertilizer, you should stop fertilizing them immediately and water the plants thoroughly to flush out any excess salts in the soil.
Using a slow-release fertilizer is a good idea, as this will help to prevent nutrient overload and ensure your daylilies get the necessary nutrients over time. Additionally, you can use a liquid fertilizer in tandem with slow-release fertilizers to provide your daylilies with an adequate supply of nutrients.
Organic fertilizers, such as compost or well-rotted manure, can also provide essential nutrients without the risk of burning your plants. However, you should apply them sparingly, as too much organic matter can create an imbalance in the soil and cause yellowing leaves.
11. Pest or Disease Infestation
Daylilies can be susceptible to insect infestations and diseases, which can cause the leaves to turn yellow.
Yellowing leaves caused by pests are usually found near the bottom of the plant. If you notice that the bottom leaves of your daylilies are yellowing, check for insects or larvae on the plant.
A wide variety of pests can cause yellowing leaves on your daylilies.
The most common include:
- Aphids
- Thrips
- Caterpillars
- Mites
To get rid of these pests:
- Treat the plants with insecticidal soap or horticultural oil to kill the insects. These products are safe for plants and can be applied as a spray or a drench.
- Treat the plants with a fungicide to prevent and control disease infestations.
- Prune off any affected leaves, as this will help reduce the infestation spread.
Diseases can also cause yellowing leaves on daylilies. Common diseases including rust, crown rot, and leaf streak need to be treated.
These diseases are caused by fungi and can be controlled with a fungicide. Pests can also carry and spread these diseases, so it’s important to handle any pest infestations to prevent disease.
If you suspect your daylilies are affected by a disease, you should:
- Prune off any affected leaves to reduce the spread of the disease.
- Treat the plants with a fungicide to prevent and control further infection.
- Add organic matter to the soil to improve the soil structure and help prevent diseases.
Monitor your plants regularly and take action immediately if you notice any signs of pests or disease. Once the problems have been eliminated, water your daylilies regularly to help them recover.
In treating the affected plants, you should also take measures to improve the growing environment.
This includes:
- Improving air circulation around the plants
- Increasing drainage in the soil
- Avoiding overcrowding
All these steps can help prevent the spread of disease and ensure your daylilies remain healthy throughout their lifecycle.
Conclusion
Daylilies are beautiful and hardy plants that can add a splash of color to any garden. However, they can be susceptible to various problems, including yellowing leaves. The causes of yellowing leaves vary and can range from simple issues, such as too much water or fertilizer, to more severe problems, like insect infestations and diseases.
Fortunately, yellowing leaves can be prevented and treated with proper care and maintenance. Regular monitoring of your daylilies is essential for detecting and resolving potential problems before they become too serious.
