Why Rhododendrons Turn Yellow?
Here are some answers to that age-old question
Let me say that I consider the Rhododendron one of my all-time favorite scrubs!
There are many things in life that we still don't understand. One of these mysteries is why rhododendrons turn yellow as they age. This question has puzzled people for years, and there is still no clear answer. Some experts believe that the rhododendron's chlorophyll production decreases as it ages, making the yellow pigments show through more prominently. Others believe that the leaves produce less sugar as they age, which causes the yellow pigments to become more visible. No one knows what causes rhododendrons to turn yellow, but it is an exciting phenomenon nonetheless!
Our love affair with rhododendrons began for us about six years ago. We moved from the "low country" of South Carolina to the "high country" of Boone. Our previous yard was only a quarter of an acre and required constant upkeep and maintenance. However, when we moved to the high country bought a home located on over 2.5 acres and all-natural. And a good chunk of the all-natural is covered in rhododendron shrubs. So, for the past six years, rhododendrons have become a part of our lives - and we still don't understand why they turn yellow!
But that hasn't kept me from continuing to try and understand more and more about this remarkable shrub. I'm amazed at the toughness and resilience they display up here in the harshest of conditions.
When it comes to rhododendrons, there are many things to consider. One of those considerations is whether your plant is healthy. If you notice that your rhododendrons are turning yellow, it might mean something is wrong with your plants. There are several reasons why rhododendrons turn yellow during the fall season. To learn what causes yellow leaves on your rhododendrons, read on.
Even though we might not understand how and why Rhododendrons turn yellow, here are some of what is thought to be the "common causes."
The most common cause of the yellowing of Rhododendron leaves is a lack of nutrients. This happens when the plant lacks sunlight or water during summer. If you notice that your Rhododendron plant is losing its green color, check whether there is adequate light and moisture. You might also want to ensure the soil is well-drained and regularly fertilized.
Another reason why Rhododendrons turn yellow is that they do not receive enough sun. If your plant is located indoors, it could suffer from a lack of sunlight. In addition, indoor plants require extra attention and watering. They often look healthier outdoors, where they can enjoy the sunshine and rain.
If your Rhododendron is getting too much sun, it could become stressed. Overly bright light can damage the photosynthetic process, causing the leaves to turn grayish brown. To avoid this problem, move your plant away from the windows.
Rhododendrons also tend to lose their color when they are exposed to extreme temperatures. For instance, if your plant is situated near a heater or air conditioning unit, it could suffer from heat stress. As such, it needs to be moved to a cooler location.
In addition, Rhododendrons can develop certain diseases that lead to yellow leaves, including mildew and rust. These conditions usually occur when the plant is subjected to excessive humidity. However, if your plant is located in a damp area, it could be affected by fungal disease. Therefore, you must watch for signs of dampness around the base of the plant.
A detailed look at the reasons Rhododendrens turn yellow
Imbalanced PH Soil
The Rhododendron plants grow best in slightly acidic to neutral soil. If the soil becomes too alkali, it causes the plant to develop yellow leaves. This occurs because the plant needs sufficient levels of calcium and iron. However, when the soil becomes overly alkaline, the plant absorbs excessive amounts of calcium and deficient amounts of iron.
When you notice your Rhododendron plants' leaves turning yellow, it is important to test the soil pH level. A home pH tester can help you determine whether your soil is too alkaline or acidic. To find out how much potassium there is in your soil, add one teaspoon of potash fertilizer to each gallon of water. Wait three days and examine the solution. A blue tint indicates potassium.
If your soil is too alkali, you'll want to apply some sulfur to lower the pH. Sulfur helps increase the availability of nutrients such as phosphorus, magnesium, zinc, manganese, copper, boron, and molybdenum.
You can also use compost tea to balance the soil. Compost tea contains beneficial microorganisms that improve the health of plants. For example, compost tea increases the absorption of nitrogen, phosphorous, calcium, magnesium, iron, and zinc.
Improper Watering
The leading cause of the yellowing of Rhododendron plant leaves is an improper watering schedule. This plant likes to be watered according to its needs. But how exactly does it know what it needs? And how often should it be watered? Let's find out.
Most plants, including the Rhododendrons, are sensitive about their watering schedules and characteristics. So, it's essential to understand how each plant reacts to different kinds of water and how that affects its health.
In the case of the Rhodoendrums, the leaves don't like to be directly sprayed with water. Instead, they prefer to drink up the moisture from the ground. Therefore, the best way to water them is to sprinkle the surrounding area with water.
When given too much water, their leaves react by developing yellowish colors. If you notice such symptoms, take action immediately and stop giving them water.
As soon as the yellowing starts, try to reduce the amount of water you're providing. Then, wait a few days and check again. If the problem persists, consult a professional gardener.
Inadequate Lighting
The Rhododendron plant likes bright, indirect light. When exposed to too much direct sunlight, its leaves turn yellow. This phenomenon is called photomorphogenesis. In contrast, the leaves are pale green when the plant gets too little light. This is known as cryptomorphogenesis.
Photomorphogenesis occurs because plants use chlorophyll to absorb sunlight. Chlorophyll absorbs red wavelengths of light and reflects blue wavelengths. As a result, the plant turns red under direct sunlight. Cryptomorphogenesis occurs when there isn't enough chlorophyll to reflect the blue wavelengths of light. Instead, the plant appears green.
Rhododendrons are native to the Himalayan region of Asia. They're often used as ornamental shrubs. However, they're also popular garden plants. Most rhododendrons bloom during springtime. Their blooms range in color from white to pink. Some varieties have large clusters of petals. Others have single blossoms.
Incorrect Fertilization
Several factors can cause the yellowing of Rhododendron leaves. One of the most common causes is poor nutrition. If you notice that your plant's leaves are starting to turn yellow, check whether it requires additional nutrients. A good quality fertilizer is essential for any plant's healthy growth. Be sure to buy a slow-release fertilizer explicitly formulated for Rhododendrons. You can also try applying a diluted liquid fertilizer directly onto your plant's foliage.
Another possible reason for the yellowing of Rhododendron leaves is too much water. When watering your plant, make sure to do it properly. Water deeply enough to reach the roots, but don't let it sit there for long periods. If your plant receives too much water, it may start to rot. To avoid this problem, you can apply a concentrated fertilizer solution directly into the soil around the root system. This will help nourish your plant while keeping it hydrated.
Salt Accumulation
Rhododendrons are among the most popular houseplants because of their long blooming season and beautiful flowers. However, many people do not realize that properly caring for these plants could be tricky. One such problem is salt accumulation. Salt accumulates in the soil around the roots of Rhododendrons. This causes the leaves to turn yellow, making the plant look sickly. In extreme cases, the leaf color turns brown, and the plant dies.
While there are several reasons why Rhododendrons accumulate salt, one of the biggest culprits is too much fertilizer. Overfeeding a plant with high amounts of nitrogen and phosphorus can cause the leaves to become discolored. If the leaves turn yellow, the plant has likely been fed too much fertilizer.
Another common reason for salt accumulation is overwatering. When the soil dries up, the roots cannot absorb enough moisture. So, watering your Rhododendron regularly can help prevent salt buildup. You should make sure to keep the soil moist but not soggy. Also, try to avoid adding fertilizer directly into the soil. Instead, sprinkle the fertilizer onto the surface of the potting mix.
There are some things that gardeners can do to reduce salt accumulation in Rhododendrons. First, they can wash off the soil from the base of the plant once every three months. Second, they can cut down on the amount of fertilizer used. Third, they can add calcium chloride to the soil to counteract the effects of chlorine in tap water. Finally, they can always use room-temperature water.
Repotting
Rhododendrons are among the most popular houseplants because of their easy care requirements. They grow best in well-drained soils rich in humus and nitrogen. When buying a rhododendron, ensure it has healthy roots and leaves. If it does not look healthy, do not purchase it.
The ideal size for a rhododendrons container is about five times bigger than the root ball. This allows the plant to develop strong branches and leaves without being crowded out of space. You should re-pot your rhododendron once every two years.
To re-pot your rhododendrons, loosen up the old soil around the base of the plant, add a layer of the fresh potting mixture over the entire surface area, and tamp down firmly. Water thoroughly. Do not let the soil dry out while watering.
Humidity Requirements
The Rhododendron is one of many plants that prefer moderate moisture levels, ranging between 60% and 80%. This moisture level is quite high; therefore, keeping it up can sometimes be troublesome. If placed in too much water, the plant may turn yellowish leaves. To prevent this, mist your Rhododenron's environment or group together your houseplants. A good way to test how moist your home is is to use a moisture meter.
Diseases and Pests
Rhododendrons are popular plants because of their beautiful flowers and long blooming season. But many diseases and pests can affect the health and appearance of your rhododendron. The most common include powdery mildew, rust, aphids, spider mites, Japanese beetles, whiteflies, and slugs.
If you notice yellow patches or spots on your plant, it could be infected with a fungus called powdery mildew. This disease causes leaves to turn brown and curl up, making the plant look sickly. Powdery mildew usually appears during warm weather but can spread quickly over wet soil. To prevent further damage, try spraying your plant with fungicidal soap. You can find it at garden centers and nurseries.
Another common problem among rhododendrons is spider mites. These small insects feed on the plant sap, causing leaves to wilt and drop off. Spider mites also produce tiny webs around the base of the plant where water collects. To control these pests, apply insecticidal soap sprays to the leaves undersides and the webbing area near the bottom of the plant. When applying insecticidal soap, make sure to follow label directions carefully. Do not use too much.
In conclusion
Yellowing is one of the most common problems that occur in rhododendrons. It is caused by several factors such as improper fertilization, lack of sunlight, insects, disease, etc. The best thing to do is to keep an eye out for any signs of yellowing and take action immediately.
