If you’ve never had a vinca, or if you’ve had one and it has turned yellow, don’t worry, you’re not alone. Vincas are beautiful plants, but they also have certain characteristics that make them susceptible to the disease that causes their leaves to turn yellow and fall off. In some cases the leaves just fall off on their own. If this happens to you or your vinca is just turning yellow, don’t worry, because there are steps you can take to help it return to its vibrant green appearance. First, let’s take a look at the cause of the change in color.
The most common cause of yellowing leaves in vincas is a fungus called Saprolegnia. It’s actually a group of fungi that produce a toxic substance known as ergosterol. This toxic substance is part of the plant’s defense system against invading organisms. As the name suggests, the toxins cause yellowing leaves in the early stages of spoilage.
If you’ve already had a bleach-water approach to killing the germs that cause yellowing leaves, you’ve probably noticed that the treatment doesn’t last very long. You might have tried other annual vinca fertilizer applications as well, and they’re all to no avail. To improve the life of your plants, you need to give annuals a more intensive soil preparation. If your soil is heavily polluted with nutrients like nitrogen and phosphorus, you’re wasting valuable organic matter even if you’re only using a tiny amount of fertilizer.
There are two things you can do to improve your soil’s nutrients without introducing any additional chemicals. First, if your soil is heavily fertilized, consider limiting your fertilizer to a once-a-year application. Instead, apply a light application of a non-toxic composted bark, a natural remedy for preventing and controlling root diseases that’s safe on your lawn and garden. Applying a composted bark to your annual vinca plantings will kill off any fungal infections and encourage new, disease-free leaves.
Fungal growth that occurs on new leaves is actually a symptom of an existing root disorder. This disorder usually starts at the base of a damaged or diseased root system, where a fungal infection occurs and damages the phloem and water-retaining cell walls. Phloem is the source of plant nutrients including nitrogen, calcium, and magnesium. While it’s important for your annuals to get enough calcium and phosphorus, they don’t need any of the other important trace minerals to survive.
To control the yellowing leaves, fertilize your plants every three weeks during the growing season. If you have an established root system, you can increase your nitrogen and potassium levels in the soil every three months. Apply organic mulches, which will help retain moisture and prevent root rot. Make sure you follow the instructions on your fertilizer package, making sure you follow the amount specifically stated on the box. Fertilizer that is too loose or application that is too thick can cause yellowing leaves and damaged roots.
Overwatering is another cause of why are my vincas turning yellow. When you overwater, you allow your plants to become dehydrated, which then kills the root system. Both the roots and the leaf discoloring happen when there’s too much water. If you think you’re overwatering, stop watering for a week or two and wait until the water stops draining from your plants’ roots. After that, lightly mist the plant with a light amount of water to recover from the previous water loss.
Many people who grow indoor plants don’t realize it, but there is a direct cause of why are my vincas turning yellow-and it’s related to their exposure to ultraviolet rays from the sun. Even though vincas naturally live in the sunlight, they still require extra UV exposure for good color. One way to ensure they don’t develop this yellowing problem is to shade or move your vinca plants to a part of the house that has less sun exposure. This may seem like a lot of work, but you’ll be glad you did once you see the dramatic difference in color. Your vincas will thank you!
