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spiny amaranth · Amaranthus spinosus

Why are there spots on my spiny amaranth leaves?

Spots on spiny amaranth are less common and usually point to fungal issues caused by high humidity or poor airflow. Check the undersides of the leaves first to rule out pests.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Inspect the underside of the leaves for tiny insects.
  2. Check if the soil is staying wet for too long.
  3. Look for signs of white fuzzy mold on the leaves.

Likely causes

  1. Fungal Leaf Spot

    Possible

    How to tell: You will see circular brown or black lesions that may have a yellow halo around them. These spots often appear after periods of heavy rain or overhead watering.

    What to do: Remove the affected leaves immediately to stop the spread. Improve airflow around the plant and avoid wetting the foliage when you water.

  2. Aphid Damage

    Possible

    How to tell: Small yellow or necrotic spots appear where aphids have been feeding on the sap. Look for tiny insects clustered on the stems or leaf undersides.

    What to do: Spray the plant with a strong stream of water to knock the aphids off. If they persist, apply insecticidal soap every 5 to 7 days until they are gone.

Leaf spots on other plants

Find out what's wrong with your spiny amaranth

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

Worry if the spots are spreading rapidly across the entire plant. A few small spots on older leaves are usually nothing to stress about.

Stopping it coming back

Keep the foliage dry by watering at the base of the plant and ensure it has plenty of space for air to circulate.

Spiny amaranth: spots? Check yours with a photo

Every plant is a little different. Take a photo of your spiny amaranth 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.

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Questions people ask

Should I cut off all the spotted leaves?
Yes, removing damaged leaves helps the plant focus its energy on healthy growth. Just make sure to use clean scissors.
Can I use a fungicide?
You can, but it is rarely necessary if you fix the airflow and watering habits. Focus on cultural changes first.

Guides to these causes

More problems with spiny amaranth

Back to the spiny amaranth 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.