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Why Are the Leaves on My Mandevilla Turning Yellow? | Growgardener!

The Mandevilla comes with a gorgeous bloom which can easily brighten up any summer lawn.

They usually thrive outdoors in the open sun, but you can also grow Mandevilla indoors with the right conditions. The plant also has another name called the Rock trumpet. This plant will surely be at the top of your wanted list if you have a flower garden.

However, Mandevilla plants can sometimes have a few health issues.

If you don’t fulfill the proper environmental conditions and requirements, you will notice the leaves of the plant turning yellow, which can leave you wondering, why are the leaves on my Mandevilla turning yellow?

The leaves of the Mandevilla plant can turn yellow for several reasons.

If you have been facing this issue without much information, keep reading as we explore the reasons behind your problem!

Mandevilla leaves turning yellow—why are the leaves on my Mandevilla turning yellow
Why are the leaves on my Mandevilla turning yellow? – Image via Reddit.

Why Are the Leaves on My Mandevilla Turning Yellow?

Why are the leaves on my Mandevilla turning yellow, you say?

To be honest, there is no one answer to this question, as the yellowing of leaves could be happening for several reasons.

But know that the yellow leaves almost always show that the plant is in danger and you are not fulfilling one or more of the essential requirements for the healthy growth of the plant.

In some cases, the yellow leaves could only be a sign of a natural process where the leaves gradually die after changing colors. If the yellowing of leaves in Mandevilla is not a part of the natural process, you must learn about the potential causes and take immediate steps to rectify the situation.

Let’s find out the top reasons!

1. The Aging Process

Plants have a lifecycle that they must go through, and once they reach the end of the cycle, a part of the foliage dies.

Mandevilla plants also have a natural lifecycle. They grow, become young, bear flowers, mature, and finally die after a specific age.

  • The leaves will turn yellow when the Mandevilla plants reach the end of their lifecycle.
  • So, if the foliage on your Mandevilla bushes is changing colors to yellow, it could be nothing to worry about and just a part of the natural aging process.
  • Look for signs of yellowing at the base of the plant.
  • If you see the entire plant turning yellow beside the leaves, there is a high chance of this happening due to age and the plant’s lifecycle.

Once the plant reaches the end of the cycle, there is not much you can do to revive it. When the next growing season comes, you can get more Mandevilla plants in your garden again.

2. Improper Watering

So, why are the leaves on my Mandevilla turning yellow? Improper watering schedules or techniques can cause the Mandevilla plant to turn yellow.

The color change can occur due to both overwatering and underwatering.


Overwatering is when water accumulates in the soil and around the roots, ultimately causing suffocation of the plant.

  • This can happen if you water too much and too often.
  • As it takes time for the plant to absorb water, the excess water will clog the soil and gather around the roots.
  • Excess water can also accumulate if the soil is old and non-porous.
  • Moreover, overwatering can also occur if the draining holes in the pot get blocked.
  • The water won’t be able to leak out, and the soil will retain excess water, leading to waterlogged soil and root rot.
  • Overwatering clogs the soil and prevents oxygen from reaching the roots, which can cause the leaves to turn yellow.

It can be identified by soggy soil and drooping leaves.


Underwatering is another issue that can cause the plant leaves to turn yellow.

  • You may forget to water the plants due to a busy schedule or give them too little water (just enough to cover the surface).
  • That can cause dehydration in the plant, and subsequently, you will notice the plant leaves curling up from the tip and turning yellow.
  • When you underwater a plant, the leaves turn crisp and curly with dry soil.

Fortunately, you can combat both these conditions by taking a few steps.

  • If you notice signs of overwatering, check the pot to see if the draining holes are open and working fine.
  • You may also have to change the soil if it has been too long for the Mandevilla plant in the pot with the same soil.
  • Also, ensure you add water only as required and not in excess.
  • To counter underwatering, you need to add more water.
  • Depending on the severity of the damage, you may be able to revive the plant with a few deep watering sessions.
  • Make sure to build a proper watering schedule and stick to it so you won’t forget to water the Mandevillas.
  • If you end up overwatering the plant, remove it from the soil, let it dry in the sun for a while, change the clogged soil, and place it in new soil.

The rule of thumb to check the soil’s moisture is to stick a finger or a moisture meter in the ground. Ensure the top 1–2 inches of the soil are dry before watering your Mandevilla.

Why are the leaves on my Mandevilla turning yellow It is always better to check the soils moisture level before watering
Why are the leaves on my Mandevilla turning yellow? It is always better to check the soils moisture level before watering – via Reddit

3. Deficiency of Nutrients

The Mandevilla leaves will also turn yellow if the plant does not receive the proper nutrients from the soil. The soil could be deficient in essential nutrients and may need fertilizer as a boost.

While several nutrients are required for the plant’s healthy growth, a few essential ones factor in the plant turning yellow.

Iron, zinc, manganese, and nitrogen are those vital nutrients that play a critical role in the Mandevilla turning yellow.

In Mandevilla plants, iron deficiency is more commonly observed.

Iron deficiency can be spotted by looking at the younger leaves of the plant. Locate the new foliage at the bottom of the plant and observe if they are turning yellow. If the answer is positive, this could be due to the deficiency of iron in the plant.

Nutrients like nitrogen, zinc, and more may represent deficiencies in older plants. To combat these nutrient deficiencies, you will have to add fertilizer which is abundant in the nutrient that is missing from the soil.

Another point to remember is that the soil must have the correct pH for the plants to absorb the nutrients properly. The ideal pH of soil for Mandevilla plants is between 6–7.

These plants prefer neutral soil. Any lower or higher pH than that will create an issue for the Mandevilla to absorb iron and other nutrients.

4. Diseases

A few pests and fungal diseases can take over the Mandevilla plants and cause the leaves to turn yellow.

Brown spots on the leaves are one of the common symptoms. Some insects and pests can also attack the plant and leave it with a deficiency of essential nutrients.

Mealybugs, whiteflies, spider mites, scales, and a few more pests can attack and suck the life out of the plants, causing the leaves to turn yellow.

It is not easy to spot an early pest infestation.

  • Mostly, the insects can be found at the underside of the leaf, forming webs and patterns and leaving behind secretions of sticky fluids.
  • Gradually, the infestation can creep up and take over the top of the leaves as well.
  • At this point, you will have to take the help of an insecticide to save the plant.
  • If you catch the pests early, you can prune the infected leaves and burn them to save the rest of the plant.
  • You can also eliminate a controlled infestation by spraying the leaves with a fast water jet.

You must be vigilant and be on the lookout to ensure you catch the signs of pests early and treat them accordingly.

If the attack has spread too wide, you might have to throw the plant away to save the entire batch.

Why are the leaves on my Mandevilla turning yellow? – Mandevilla & Dipladenia Care | Outdoor & Indoor Care of Mandevilla & What’s The Difference? – YouTube


Why are the leaves on my Mandevilla turning yellow, you asked? I hope I was able to answer the question.

There could be several reasons for this occurrence.

  • You may not be providing the correct prerequisites for the plant to thrive, or it could be a part of the natural aging process of the Mandeville plant.
  • Check for the proper water needs of the plant, make a watering schedule accordingly and stick with it.
  • Proper lighting, nutrition, and disease protection are ways to keep the Mandevilla plant happy and thriving with no yellow leaves.

Don’t be demotivated at the sign of the yellow leaves. If you put effort into it and keep providing the right growing conditions, you will soon have lush green foliage instead of yellow.

Happy planting!