Dahlia Leaves Turning Yellow: Causes and Remedies

There are various factors that triggered Dahlia leaves turning yellow abnormally.

dahlia leaves turning yellow

It could be a sign of wrong watering frequency to disease, insect infestation and other conditions relating to wrong caring practices.

Few flowers can rival the dahlia’s breathtaking beauty and dazzling array of colors.

With their diverse forms and majestic presence, it’s no wonder that these stunning plants have captivated the hearts of enthusiasts worldwide, even inspiring conventions and contests in their honor.

Dahlia Leaves Turning Yellow: The Causes

Determining the cause of ailing plants can sometimes be a detective’s task.

However, if you notice the yellowing towards the end of the growing season, it may simply be your dahlia preparing for its natural dormancy period.

In contrast, if yellow leaves appear early in the growth cycle, it’s time to investigate further.

dahlia leaves turning yellow

Cultural Reasons

In the early stages of growth, your dahlias may be signaling their dissatisfaction with the soil or cultural conditions.

These sun-loving beauties thrive in slightly acidic soil and full sun exposure.

To keep them happy, ensure they receive a deep watering once a week.

  • Heavy clay soil can hinder proper drainage, leading to waterlogged roots and tubers.
  • Improper soil pH and condition are common culprits behind yellowing leaves.
  • Lack of essential nutrients, such as magnesium or iron, can also cause dahlia plants to turn yellow.


Rot and fungal diseases frequently take center stage as the primary cause of yellow dahlia foliage.

dahlia leaves turning yellow

Here are some disease-related factors to watch out for:

  • Rotten tubers cannot support healthy foliage and blooms, resulting in faded leaves and yellowing.
  • Smut, a fungal disease, manifests as yellow mottling on the leaves.
  • Chlorosis, characterized by the plant’s inability to produce sufficient chlorophyll, gradually fades the leaves into a pale yellow hue.
  • Verticillium wilt, a vascular disease, causes wilting and fading of the leaves.
  • Mosaic diseases leave irregular patches and spots of yellow on the leaves.

Dahlias face no shortage of disease pathogens eager to attack them. However, with proper care, these plants can usually survive until their dormant phase.


dahlia leaves turning yellow

In addition to diseases, various insects can infest dahlia plants, leading to yellowing leaves. Keep an eye out for the following culprits:

  • Leafhoppers take center stage as the most prevalent pests of dahlia plants. Their feeding habits can transmit a disease known as “the yellows.”
  • Armored scale is another contributor to yellow dahlia foliage.
  • Aphids may cause yellow or white damage accompanied by twisted and distorted leaves.
  • Mites are sucking insects that prefer lower leaves and shady spots, causing damage to the foliage.

Though sucking insects can be detrimental to the plant’s health by reducing the availability of plant sugars, they seldom cause plant death.

Combat their damage by simply rinsing dahlia leaves with water to dislodge them.

Additionally, horticultural oils, soaps, or neem oil work effectively in deterring these pests from your cherished dahlia plants.

dahlia leaves turning yellow
Neem Oil

Best 10 Varieties of Dahlia to Grow in Your Garden

  1. Café au Lait:
    • Known for its large, dinner-plate-sized blooms, Café au Lait dahlias feature creamy, blush-pink petals. They are prized for their stunning and sophisticated appearance.
  2. Bishop of Llandaff:
    • This dahlia variety has deep, dark foliage and vibrant, single, scarlet-red flowers. The contrast between the dark leaves and bright blooms makes it a striking choice.
  3. Thomas Edison:
    • With rich, deep purple, nearly black blooms, the Thomas Edison dahlia adds a touch of drama and elegance to the garden. The flowers are large and double.
  4. Gallery Art Deco:
    • A smaller dahlia variety, Gallery Art Deco, produces vibrant, bi-colored blooms with a mix of deep red and white. It’s well-suited for borders or container gardens.
  5. Dinnerplate Dahlia:
    • As the name suggests, these dahlias have enormous, plate-sized blooms that can reach up to 12 inches in diameter. They come in various colors, adding a bold statement to your garden.
  6. Karma Choc:
    • This dahlia features deep, velvety, dark red flowers. Karma Choc is a medium-sized dahlia with an alluring, almost chocolate-colored appearance.
  7. Cactus Dahlia:
    • Cactus dahlias have unique, spiky, and quilled petals, giving them a distinctive look. They come in a range of colors and add texture to flower arrangements.
  8. Mignon Single Dahlia:
    • This smaller dahlia variety produces charming, single blooms with vibrant colors. Mignon Single Dahlias are excellent for cutting and are great for adding pops of color to gardens.
  9. Babylon Bronze:
    • Babylon Bronze dahlias have bronze-orange petals with a touch of yellow. The flowers are semi-cactus in form and create a warm and inviting display.
  10. Snowflake Dahlia:
    • With its unique, delicate appearance, the Snowflake Dahlia features white, star-like blooms with a touch of elegance. It’s a standout choice for borders or mixed plantings.
dahlia leaves turning yellow
Left to Right: Café au Lait – Cactus Dahlia – Karma Choc

With a little extra care, you can prevent yellowing dahlia foliage and enjoy superior blooms and vibrant leaves all summer long.

Remember to provide the ideal soil conditions, monitor for diseases, and keep pesky pests at bay.

Your little piece of the garden will thrive, showcasing the true glory of the magnificent dahlia.