Dahlias are exotic flowers and a gardener’s dream. Those who grow dahlias know that they are prone to curling leaves, but do not know its reasons and solutions.
Your dahlia leaves can curl due to varied reasons like overwatering, underwatering, temperature stress, Virus attack, Insect attack, or, Nutrient Deficiency, etc.
The curling of leaves is a sign that conditions for Dahlia are not optimum and you would need to make some changes for it to grow well.
To resolve this, you would need to understand the reason behind the curling of dahlia leaves and take corrective measures for the same.
Let us look at each of them in detail below.
1. Overwatering
Dahlias are prone to Overwatering and it is one of the most common causes of curling of the leaves.
It causes the roots to submerge in water and devoid the plant of the necessary nutrients to grow.
Overwatering of Dahlia can happen due to either watering it too often or drainage is not proper.
Symptoms of overwatering
Overwatering of Dahlia often shows in the curling of the leaves and changing of leaves’ color to Yellow.
Tips to revive
If you have found that your Dahlia has been overwatered, you should stop watering until the soil is dry. It can take approx 3 – 5 days.
Once it is dry, water your Dahlia twice a week.
Preventive Measure
- Water your Dahlia strictly according to the schedule.
- Check if there is sufficient drainage for the water to pass through.
- Provide increased airflow, a little high temperature, and lower humidity.
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2. Underwatering
Though Overwatering is the most common reason for Dahlia leaves to curl, underwatering can also be the cause of curling.
Underwatering happens when the water supply is less than required. This can either be due to loss of water due to transpiration from large leaves being more than the water supply provided to your Dahlia.
Symptoms of underwatering
Lack of water causes the Dahlia to curl to retain moisture. You will notice the curling of leaves at the tips.
Tips to revive
- Water the Dahlia generously until water starts to come out from the base of the pot.
Preventive Measure
- Strictly follow the watering schedule. Usually, you need to water the Dahlia twice a week.
- Proactively check the Dahlia and water it once the top 1-2 inches of the soil is dry.
3. Temperature Stress
The curling of Dahlia leaves can be caused due to both hot and cold climates.
Dahlias are native to Mexico and Central America and hence it not acclimatized to too cold frosty weather. Thus Dahlias are usually kept indoors in pots in colder regions.
High temperature may also cause the wilting of the leaves as water transpiration increases.
The ideal temperature range for Dahlia to grow is 60-95°F (15-35°C).
Symptoms
Curling can be due to temperature stress if the plant is experiencing a temperature range beyond 60-95°F (15-35°C)
Tips to Revive
Providing an optimum temperature range usually helps Dahlia to revive. In case your area is experiencing a heatwave, ensure the watering of Dahlia is as per the schedule and continue to check the top 1 – 2 inch soil for dryness.
Preventive Measure
- Avoid planting Dahlia in a temperature range beyond normal.
- It should not be close to heating or cooling devices.
4. Diseases
Dahlia leaves can curl due to diseases as well. The cause could be a virus for example Begomoviruses or fungal diseases like Leaf Spots or Mold.
The virus can be spread by whiteflies.
Symptoms
- Stunted growth
- In case of Virus – Dark & swollen veins
- In the case of Mold – Leaves would be irregular in shape and have molds on them.
Tips to revive
Remove the infected part of the plant. In case of fungal infection, apply a copper-based fungicide.
Preventive Measures
- Use Virus-free seeds in case you are growing your Dahlia using the seeds.
- Using an insecticide or preferably Neem oil can help to reduce the spread of whiteflies and other fungal diseases.
5. Pests
Pests are also one of the major causes for the Dahlia leaves to curl. Below are a few that your Dahlia can be infected with.
- Aphid
- Thrips
- Whitefly
- Mite
These insects feed on the leaf sap causing it to curl. Aphids would feed on the top of the leaves whereas Thrips feed on the bottom.
Symptoms
- Upward curling of the leaves with the presence of Aphids and shiny honeydew.
- Downward curling of leaves with the presence of Thrips at the lower side of the leaves.
- Mites’ presence can easily be noticed by carefully observing for webs.
Tips to revive
- Applying Neem oil is the best solution until the infestation is severe.
- In case of severe pest infestation, you may apply stronger insecticide.
Pro Tip – If the curling of the leaves is scattered here and there, this could be a pest infestation. And if the curling of leaves is concentrated, this could be a disease.
6. Nutrients Deficiency
Dahlia like other plants requires nutrients like Nitrogen, Phosphorus, and Potassium. A lack of it can cause the curling of the leaves.
A high amount of nitrogen can cause excess foliage but fewer flowers whereas a higher amount of potassium can promote blooming.
Symptoms
- Leaves will turn yellow along with curling.
- Lesser blooming
Tips to Revive
- Apply suitable fertilizer with an NPK ratio of 4 10 10. We would recommend Lilly Miller Bulb & Bloom Food 4-10-10 4lb. You should use a fertilizer with less nitrogen and more potassium.
- Do not apply Fertilizer during winter.
Conclusion
Dahlia bears large flowers which can give a smile to any gardener. To take care of the curling of Dahlia leaves you must diagnose the cause first before taking action.
With the information given above, hopefully, you would be able to take good care of your Dahlia. Happy Gardening!
