Why Are My Dahlias Dying?

Dahlias vary in type. You can keep some at home as ornamental flowers, while some are good for drawing insects to retain your garden as healthy as possible. But there are instances when they might be dying because of some issues. We have conducted thorough research to know what causes them to die.

The reasons why dahlias die is because of the issues below:

  • Too much water
  • Lacking water
  • Inappropriate amount of direct sunlight
  • It has a poor soil
  • Pests feed on dahlias until they die

In this post, we will explain further the causes of dying dahlias and what you should do to save them. Please read on to know some tips about taking care of this particular plant. Doing so may also help you a lot on your next planting project. Enjoy reading!

Feel the change of seasons in the dahlia flowers thats are dying after the peak - Why Are My Dahlias Dying

What Causes Dahlias To Die?

garden dahlias in bloom, withered dahlia

You often don't notice that some of the reasons why your dahlias are dying are because of incorrect plant caring practices. Refer to the details below to keep an eye on these next time.

1. Too Much Water

flowers of dying yellow dahlias with dead petals, abstract, sad

You should always keep the soil of your dahlias moist but not to the point that too much water sits on it. A typical error of beginners with dahlias is that they overwater it during the spring.

When dahlias begin to grow, they won't hold much foliage. Consequently, they won't require too much water in this stage.

Expert dahlia gardeners advocate waiting until the summer to water them when they have a lot of leaves, and the temperature is much higher in temperate areas. It is when there is the most demand for water. However, this is contingent on your region's hot spring.


  • Dry brown leaves
  • There is mold build-up on the stems and surface of the soil
  • The flowers are brownish on the edges
  • The leaves' edges are dry and brown
  • You can notice the tubers have soft wet areas if you dig them up


  • It would be best not to water your dahlias on a daily basis during the spring, especially if you have just planted them
  • Keep the soil moist but not soaked
  • If your dahlias are newly planted, it will help to water them once a week
  • You should prevent your dahlias from sitting too long in the water

2. Lacking Water

Beautiful close-up of a wilted dahlia

When dahlias are young and have little foliage, it is pretty easy to overwater them. However, they require a lot of water as they begin to grow and when the temperature is too high. The soil should not be drenched even if the dahlia is fully developed. You must, however, ensure that the soil is wet.

It is very dependent on your local climate and soil type. Overwatering and underwatering have very similar symptoms. However, closer inspection reveals whether they require additional water.


  • If you notice that your dahlias didn't bloom
  • The flowers and leaves are dry, crispy, and brown
  • If you see that the soil of your dahlias is dry to the touch, especially during summer
  • The leaves of your dahlia plants contain yellow spots or entirely yellow


  • Dip a finger two inches into the soil. If you don't feel any moist, it would be best to water the dahlias
  • It would help to water your dahlias twice every day; every morning and evening during summer

3. Inappropriate Amount Of Direct Sunlight

Beautiful Yellow dahlia withered flower with petals isolated on a black background

Different dahlia cultivars require different quantities of sunlight. Some plants can thrive in full darkness. Others, on the other hand, require full or partial sun.

If specific dahlia kinds do not receive enough sunlight, they will grow quite tall as they reach out for more. They may also have reduced growth due to a lack of energy to transfer into growth. If kept in full or partial shade, several dahlia cultivars will die or exhibit signs of dying.


  • Dahlias that grow very tall try to reach for more sunlight
  • The leaves of dahlias are partly yellow, have yellow dots, or are entirely yellow
  • If it has only a few flowers and flower buds
  • The leaves of your dahlias are withered, and the color brown


  • You have to know the amount of sunlight your dahlias require by their variety
  • You should replant your dahlias in a location where they can get less or more sunlight
  • It would be best to clear the area around your dahlias from trees and shrubs
  • Place potted dahlias in an area where they can get the amount of sun they need
  • It will help if you experiment by planting them in various locations to know how much sunlight is suitable

4. It Has Poor Soil

Feel the change of seasons in the dahlia flowers thats are dying after the peak - Why Are My Dahlias Dying

If the soil of your dahlias has poor quality or health, it can cause water-logging or cannot retain enough moisture. Waterlogged soil is due to poor drainage. On the other hand, sandy soil can cause the soil not to retain enough moisture.

Dahlias can also die if the pH of the soil is too high or too low. Adding various things to the soil will readily cure this. And as explained below, you can also adjust the height of your dahlias on the ground.


  • You have to test the pH levels of the soil; the ideal pH is 5.8 to 6.2 for most kinds
  • Add sulfur or aluminum sulfate to a soil that has too high pH levels
  • Add hydrated lime or limestone to a soil that has too low pH levels
  • If your dahlias have poor drainage, it would be best to replant them above the soil to form a mound
  • For a soil that drains too much, it would help to replant them deeper into the ground

5. Pests Feed On Dahlias Until They Die

Beautiful Red dahlia withered flower with petals ready to fall, isolated on a black background

Slugs, black bean aphids, flea beetles, earwigs, and thrips are those insects that feed on dahlias, harming the leaves and stems. Some of these are quick to identify, but others are hard to spot due to their very tiny size.


  • There will be holes in the dahlia's leaves, which will appear as spots or can also be considerable
  • You will notice tiny bite marks
  • There are visible insects in and around the soil or on the plant's surface
  • There are missing areas on the stems
  • If the leaves are wilting, or worse, dying
  • Stunted growth or your dahlias don't develop to the usual height of their kind


  • It would be best to utilize snail and slug pellets
  • If the numbers of insects are too large, it will help if you use sticky traps
  • You can mix in a variety of plant types in the area where your dahlias are located

6. Diseases

Dahlias dying after a frost

Dahlias are susceptible to a variety of diseases that might kill them. If the problem affects all leaves, it's more likely to be an issue with the soil, pest infestation, sunlight, or watering habits. However, it might be a disease if it only affects a few leaves.


  • If you notice yellow spots on the leaves of your dahlias
  • There are white residues on the top area of the leaves
  • Tiny dark spores on the leaves' underside
  • Brown dots and dry areas on the leaves
  • If the leaves of your dahlias are falling off or dying
  • The damage on the leaves is not uniform


  • Use the mixture mentioned above and spray your dahlias after sunset
  • Utilize a natural mold-killing spray
  • Replace the potted dahlias outdoors or indoors when you observe the problem

How Many Dahlia Varieties Exist?

Dahlia is a genus of plants that comprises thousands of species. The genus contains over 40 species divided into 14 groups based on the floral type and native range. Over 20,000 recognized cultivars and variations are available, thanks to centuries of dedicated breeding and improvement.

Wrap It All Up

Like other types of plants, pests, damage, and diseases can also occur to your dahlias which cause them to die. However, with proper care and solutions, you can still save your precious dahlias from these problems.

We hope you find this post helpful. If you want to read further, you can check the articles below. And if you have additional questions, please leave a comment below.

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