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Check these first
- Inspect the undersides of the leaves for tiny insects.
- Check if the leaves stay wet for long periods after watering.
- Look for signs of mold or fuzzy growth on the spots.
Likely causes
Fungal Leaf Spot
PossibleHow to tell: This is less common for this plant, usually caused by high humidity and poor airflow. You will see small, dark, or yellowing spots that may have a halo around them.
What to do: Remove the affected leaves to stop the spread. Improve air circulation around the plant and avoid getting water on the foliage when you irrigate.
Aphid Damage
PossibleHow to tell: This is less common for this plant, usually caused by aphid infestations. You will see tiny yellow or discolored spots where the insects have been feeding on the sap.
What to do: Check the undersides of leaves for clusters of small insects. Wipe them away with a damp cloth or use a gentle insecticidal soap to treat the area.
Find out what's wrong with your spreading dogbane
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
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When to worry
Small, isolated spots are usually manageable. You should worry if the spots are spreading quickly or causing the leaves to drop prematurely.
Stopping it coming back
Water at the base of the plant to keep foliage dry and ensure there is plenty of space between plants for air to move.
Spreading dogbane: spots? Check yours with a photo
Every plant is a little different. Take a photo of your spreading dogbane and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
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Questions people ask
- Are these spots contagious to my other plants?
- If the spots are caused by a fungus, it can spread to nearby plants. It is best to isolate the affected plant until the issue is resolved.
- Can I use neem oil on my dogbane?
- Yes, neem oil can be used to treat both fungal spots and aphids. Apply it in the evening to avoid leaf burn from direct sun.
Guides to these causes
More problems with spreading dogbane
- Why are there bugs on my spreading dogbane?
- Why is my spreading dogbane growing so leggy?
- Why are my spreading dogbane leaves turning yellow?
- Why is my spreading dogbane drooping?
- Why are my spreading dogbane's leaf tips turning brown?
- Why is my spreading dogbane not flowering?
- Why is my spreading dogbane showing signs of root rot?
- Why are my spreading dogbane leaves curling?
Back to the spreading dogbane guide
This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.