Why Is My Dianthus Dying? | 10 Causes and Solutions

Dianthus flowers are sturdy and gorgeous, but if the ones in your garden are dying, it is usually could be due to rust, Fusarium Disease, Gray Rot, Spider Mite, Alternariosis, aphids or snails. The treatment for each can save your plant if you act quick.

This article will explore the top 7 causes of a dying dianthus and how to solve them.

Causes of Dianthus Dying

If your dianthus flowers are starting to die, below are a few of the reasons this might be happening.

1. Fusarium Disease

Fusarium is a disease usually caused by high acidity levels, moist soil, and high temperatures. Fusarium is found in the soil, but if the soil’s ingredients get out of whack, it can cause your dianthus flowers to start to die. The disease usually hits the weakest and most-stressed plants first, but in reality any type of dianthus plant can be a victim of it.

One of the worst parts about fusarium disease is the fact that it often isn’t detectable until it is too late to do anything about it. This is why you need to inspect your plants carefully and regularly in order to take care of problems before they get too bad.

2. Botrytis (Gray Rot)

Botrytis can affect vegetables, vineyards, and different flowers, including dianthus flowers. If you see spots on your flowers, this might be gray rot. It can affect flowers such as peonies, mums, and dahlias, as well as vegetables such as lettuce, onions, tomatoes, and beans

 If you protect your dianthus plants from too much humidity, they are much less likely to suffer with gray rot. To lessen the likelihood of gray rot, make sure your plants get a lot of ventilation and keep them away from too much humidity.

3. Spider Mite

Spider Mite like to suck the sap out of the leaves of your dianthus plants, which cause them to make yellow dots on those leaves. You’ll notice when the spiders make a web on the underside of the leaves, in which case you can spray the plant with sulfur and get rid of them.

Since low humidity usually increases the likelihood of seeing red spiders, you can also increase the humidity level around your dianthus to possibly prevent the spiders from attacking.

4. Rust

Rust is known as Uromyces Caryophillinus and is not terribly common with dianthus flowers, but it does occasionally happen. Rust is a fungal disease that takes nutrients from the plant and can live for up to six months without a host, which can make it very difficult to get rid of.

The petals of the plant are the first thing to be affected when the plant is suffering from rust, and it is especially common when the temperature is between 41 degrees and 82 degrees Fahrenheit.

5. Alternariosis

Alternariosis affects both the stems and leaves of the dianthus plant, making both of them very spotty. Unlike other diseases, Alternariosis causes purple spots instead of yellow or green ones.

Plants’ stems can break, the leaves can fall off, and if nothing is done about it, it can cause the plants to die. To avoid this, try not to let your plants get too humid, and you can also use a fertilizer that contains phosphorus and potassium.

6. Aphids

Aphids are usually very hungry insects, but once it gets very dry, they usually start leaving your dianthus plants alone.

Once they attack your plants, the plants start to look dull and lifeless, and they often leave behind a honeydew excretion that increases the odds of getting clove rust. More often than not, aphids can be eliminated by using simple fast-acting insecticides.

7. Snails

Snails may look safe and harmless, but they can do an awful lot of damage on your dianthus flower plants. If the humidity is very high or you’ve experienced a lot of rain recently, the chances of your plants getting attacked by snails and slugs are much greater.

They feed on every part of the plant and therefore can destroy the plant quickly. Set up a beer trap by filling a saucer with beer and placing it near your plants. The snails will crawl in and will die, keeping them off your dianthus.

3 Ways to Save Dying Dianthus

If your dianthus plant is dying, here are a few things you can do that might revive them:

1. Never Overwater

When there’s a problem with your flowers, it’s easy to assume they’re not getting enough water, but problems also occur when you overwater your plants. Just water them as usual and no more, waiting until the top one or two inches of soil are dry before giving them more water.

2. Make Sure You Deadhead

After they bloom, dianthus flowers need to be deadheaded because the petals will wither and fade at this point. To encourage healthy growth, prune any petals or leaves that don’t look good with sharp scissors or pruning shears.

3. Keep the Plants in the Right Environment

Before you buy a dianthus plant, do some research so you can learn about the proper soil, the right amount of watering, and anything else that is needed to help the plants grow and thrive.

They can tolerate up to six hours of full sun a day, but will grow best in part shade. These are also plants that return year after year for a very long time, so you can enjoy them for many years to come.

Check out this video for tips to keep your dianthus flowering for longer.


Dianthus plants have beautiful blooms but need to be watched carefully for problem areas. These include diseases such as fusarium, gray rot, and rust, as well as pests such as aphids, snails, slugs, and red spiders. You can usually take care of these problems easily.