Mandevilla is a beautiful plant that is mainly considered low maintenance. They also go by the name Rocktrumpet and are a flowering vine species. They grow naturally in tropical climates, so they need lots of sun and water. While they are low maintenance, some issues can cause harm and may lead to death if not cured.
A Mandevilla plant may die due to fungal or bacterial diseases, improper watering, temperatures below 45°F (7°C), or a lack of direct sunlight about 6 to 7 hours per day. If a disease isn’t what is harming your Mandevilla, though, it may be worth looking at environmental stressors and whether your plant is getting enough sun.
Outside of these diseases, Mandevilla does well in warm temperatures and wet environments. Your Mandevilla plant will grow and thrive as long as they get a good amount of sun, water, and the right amount of fertilization. They can do equally well indoors or outdoors to best fit your needs.
Why Are My Mandevilla Leaves Turning Brown and Falling Off?
Mandevilla are very hardy plants, able to handle various conditions without a problem. That makes it all the more shocking when they start to have leaves that turn brown and fall off.
Thankfully, that also means that it is easier to narrow down what is causing the condition so that it can be fixed quickly and get your Mandevilla back on track.
The first and biggest issue is disease. There are issues like bacterial wilt or a variety of fungal diseases.
Bacteria and fungi are usually at play when something bothers your Mandevilla. A fungus can be responsible for various diseases, with Crown Galls being one of them. Leaf spot, Botrytis Blight, Stem Rot, and Sooty Mold are diseases from fungi that can harm a Mandevilla.
For all of them, using a fungicide is the best way to stop the disease from spreading. Additionally, you will want to remove the parts of the leaves and stems that look infected. It is also a good idea to quarantine the plant so the fungus can’t spread to other healthy plants via fungal spores.
Usually, with these fungal diseases, you will see brown spots on the leaves. Sometimes, the stems and roots will turn yellow and brown, and the leaves and twigs will wilt. With sooty mold, you will see a fuzzy coating that looks brown or black on the leaves and stems.
Bacterial wilt, as the name suggests, is caused by bacteria. It usually occurs in hotter temperatures above 85°F (30°C). The bacteria can block the tissues of the plant and prevent water and nutrients from moving throughout the plant.
Unfortunately, there is no cure for bacterial wilt, and it is usually best to kill off your plant immediately if you suspect this is the cause – this stops the disease from spreading. Sometimes, if you want to try to save it, a fungicide that contains copper seems to have the best results.
Mandevilla plants are tropical. This means that they like soil that is moist but well-draining. If a Mandevilla doesn’t get enough or gets too much water so that the nutrients are leached out, the plant may start to show brown leaves and die.
Like most other plants, you can check to see if your Mandevilla needs water using the finger test. You will stick your finger 2 inches (5 cm) into the soil to see if it is dry. If it is, then it is time to water. Usually, half an inch (1 cm) is ideal, but if more than the top two inches is dry, that is a sign that your plant is in desperate need of water.
If you don’t want to use your finger, anything that dirt will stick to, like metal or wood, can be used. Some people use popsicle sticks or chopsticks to test. Additionally, if you just want to look and see if your plant needs more water, there are moisture meters that will tell you when water levels are low.
Mandevilla needs a lot of sunlight to grow at its best. They prefer six to seven hours of direct sunlight daily. They also don’t like too much fertilizer or if it grows much colder than 45°F (7°C). If any of these conditions aren’t met, your Mandevilla may show signs of stress.
Usually, signs of stress involve the leaves turning brown and falling off in large amounts.
How Do I Bring My Mandevilla Back to Life?
Some key rules to follow to ensure your Mandevilla stays healthy and comes back to life if needed.
- It is usually best to stop fertilizing in late summer to stop your plant from becoming over-fertilized. After this time, the plant will either go dormant or slow its growth and won’t need as much fertilization.
- If you suspect a fungal infection is harming your plant, get fungicide. Follow the instructions on the fungicide to try and stop the disease from spreading. Cut back any dying or infected stems and leaves.
- Make sure your Mandevilla is getting plenty of sun. They like six to seven hours of direct sun, but in some climates, the direct sun may be too harsh for the plant. If you see your Mandevilla burning or bleaching in full sun, try to put it somewhere that it won’t get as much direct sunlight in the afternoon.
- Always keep your Madevilla’s soil moist. Don’t let it dry out; try never to allow more than 2 inches (5 cm) of top soil to dry out. Preferably, you want no more than the top half inch (1 cm) to dry out.
How Often Should Mandevilla Be Watered?
There isn’t an easy way to specify how often Mandevillas need water. They need a lot of water and don’t like their soil to dry out. For that reason, they usually do best when you check the soil’s moisture levels rather than going by a set schedule. Once you know how often to water your soil, you can start following a schedule, but until then, it is best to check to ensure before watering.
For ideal watering, check the soil. When the soil’s top half inch (1 cm) is dry, it is time to water again. For most people, this seems to be once or twice a week in summer, though some people have to water daily. This may be reduced to once a week or every ten days in winter.
Do Mandevillas Need Full Sun?
Mandevillas prefer to have full sun. As long as they aren’t getting too hot, six or seven hours of sunlight a day are best for these plants.
What Temperature Kills Mandevilla?
Mandevilla prefers temperatures around 70°F (21°C) during the day and down to 60°F (16°C) at night, however, any temperature below 45°F (7°C) can easily start to kill the Mandevilla.
Even when overwintering your Mandevilla, you don’t want the temperature to drop below 60°F (16°C), or your plant may die.
Are Coffee Grounds Good for Mandevilla?
Mandevillas don’t do well with coffee grounds. While they may get some nutritional benefits from the grounds, it also promotes fungal growth. Since fungi are one of the leading causes of diseases in these plants, it makes sense that you wouldn’t want to put something that entices it to grow in the soil.
Can Mandevilla Grow in Pots?
Mandevilla can grow in pots. This is the perfect solution for people who want to grow Mandevillas but don’t live in warm enough climates. This allows them to easily become indoor houseplants so that anyone can own a breathtaking Mandevilla.
Mandevillas are pretty hardy plants. Unfortunately, they are susceptible to many bacterial and fungal diseases that can cause them to die. Some of these, like bacterial wilt, are very harmful to the plant and are almost incurable.
Mandevilla may be hardy plants, but a few issues that may cause them to become ill or die include fungal or bacterial diseases, improper watering, or stress caused by a lack of sunlight.
Thankfully, as long as you can keep fungus away from these plants, they will grow and thrive in any warm, wet conditions. They enjoy full sun and moist soil and can be grown indoors or outdoors depending on the climate, what works best for you, and your space.