Mandevilla plant shows dying signs often due to Nutrient deficiency, Poor drainage, or Spider mite infection. Southern blight bacteria and Aphids may deteriorate the plant’s health too. Anthracnose and Powdery Mildew are also commonly seen in Mandevilla plants.
‘Mandevilla’ is a group of tropical and subtropical plants. Mandevilla is also called a Rock trumpet. It works great as an indoor plant.
Mandevilla works great indoors as it can be grown in hanging baskets. The Mandevilla flowers look showy and pretty.
What if your Mandevilla plant runs into some issues? What if it shows some dying signs? Any amateur gardener will panic.
|Chlorosis due to Nutritional Deficiency
|Test soil pH and adjust it to be neutral (6.7 to 7.5) for Mandevilla. Address Iron deficiency with Iron sulfate or coffee grounds if needed. Ensure adequate Zinc, Manganese, and Nitrogen for overall health.
|Use well-draining soil or pots with drainage holes to prevent waterlogged conditions.
|Spider Mite Infestation
|Identify spider mites by checking for webbing between leaves. Treat with Neem oil to eliminate the infestation.
|Crowded Roots/Root-Bound Plant
|Repot in a larger container with well-draining soil to provide more space for roots.
|Southern Wilt (Southern Blight)
|Caused by bacteria; Isolate and dispose of infected plants to protect others.
|Aphid infestations can cause curling; inspect and treat with appropriate insecticide or Neem oil.
|Brown Spots on Leaves
|Brown spots can be due to Anthracnose or improper watering.
|Prune dense foliage and remove affected leaves to reduce disease spread. Use horticultural oil on infected leaves if necessary.
Why are my Mandevilla leaves turning yellow and falling off?
Mandevilla leaves turn yellow due to Chlorosis and this is due to nutritional deficiency. Southern wilt turns the leaves yellow. Yellow spots are seen on Mandevilla due to Spider Mite infestation. Mandevilla plant’s older leaves become yellow and fall off. This is a completely natural process and happens with most vines.
If you see yellowing foliage at the base of the plant, it is completely natural. The plant will grow new foliage, so you need to sit back and enjoy new foliage.
There are other reasons for foliage yellowing, let’s look at them.
Mandevilla plants may suffer from nutritional deficiency due to poor soil or high pH levels in the soil. They thrive in soils that are neutral in pH(i.e., 6.7 to 7.5).
Test the soil pH and then care for your plant accordingly. There are also two types of deficiency that can be seen in Mandevilla plants.
- Iron Deficiency: If the soil lacks Iron, the yellowing starts on younger leaves and spreads to the older leaves.
- If the plant lacks Zinc, Manganese, or Nitrogen then the older plants become yellow followed by the younger leaves.
Poor Drainage in the soil is very harmful to the plants. You should make sure your potting mix has good drainage.
Poor drainage causes waterlogged conditions which in turn lead to root rot. Rotten roots won’t absorb either nutrients or water.
This causes the yellowing of the Mandevilla leaves. To prevent this use a pot with a drainage hole.
Spider mites on Mandevilla
Spider mites can infect a Mandevilla plant. The first sign of their infection is the web that is seen on the leaves.
These pests can’t be seen with the naked eye. The foliage will become bronze, dry up, and then fall off.
To treat: You can get rid of them using Neem oil.
Crowded roots/Root-bound plant
If the roots feel it’s too crowded in the pot, then they can’t absorb nutrients and thus the leaves become yellow.
- You can repot the plant in a bigger pot with better-draining soil.
- When repotting, cut off the dead parts of the root ball. Disturb the lateral roots slightly so as to increase the surface area of absorption.
Southern wilt is also called Southern Blight. This disease is caused by bacteria. When it infects your Mandevilla plant, the leaves become yellow.
Leaves may turn yellow, brown, and then fall off. If you suspect this disease in your plant, destroy the plant to prevent its spread in your garden.
Mandevilla plant leaves curling
Curling or distorted leaves on Mandevilla are mainly caused due to pest infection. They may be also caused due to Boron deficiency, but it’s quite rare.
If you see curled leaves on your Mandevilla plant, it is probably caused by Aphids. Inspect the distorted leaves to see if they are present.
How do I get rid of aphids on Mandevilla?
If you do notice them, spray them with an appropriate insecticide or Neem oil. Isolate the infected plant from the rest of your plants, you don’t want them to spread to other plants.
Mandevilla plant brown spots on leaves
Brown spots on Mandevilla leaves are caused due to Anthracnose. The foliage becomes yellow and develops brown spots. Mandevilla leaves also turn brown when the plant is watered improperly.
These brown spots usually align with the leaves’ veins. Foliage may fall off in some cases. Anthracnose infection is many times confused with other fungal infections.
For best diagnosis, send your infected plant’s samples to a laboratory. You can then treat your plant accordingly.
Mandevilla leaf spot treatment
Cut the affected leaves as soon as you see them. This helps prevent the worsening of the situation. Dispose of the infected leaves properly.
If needed, spray the plant with a fungicide like Daconil or Pageant. Use these according to the label.
Powdery Mildew on Mandevilla
Powdery mildew is a fungal disease. The spores spread via wind and germinate when there’s enough humidity, they don’t particularly need moisture.
This disease is called so because it appears as powdery growth on both sides of the leaves. This disease is easy to diagnose.
How to treat powdery mildew on Mandevilla
Selectively prune out dense growth of foliage and be sure to remove affected leaves/dead leaves to prevent further deterioration of the plant.
Spray the infected leaves thoroughly with horticultural oil if the infection is severe.
Frequently Asked Questions
People send me many questions daily via mail. Mandevilla enthusiasts mail me too. I’ll answer those questions here to help as many people as possible.
Can a Mandevilla survive winter?
Nah, they can’t survive the winter if the temperatures fall too low. You should not let the plant be in temperatures below 50F.
You can bring the plant indoors if the temperature falls too low.
How much sun does a Mandevilla plant need?
Mandevilla plants like to be in partial shade. Give your plant indirect sunlight for 6 hours a day and it’ll thrive well.
Is Epsom salt good for the Mandevilla plant?
It depends on what you are planning to do. It will increase the blooming in Mandevilla plants. Mix a teaspoon of Epsom salt mixed in water and spray it fortnightly, two times.
Epsom salt encourages the growth of new branches thus induce blooming in the Mandevilla plant.