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water smartweed · Persicaria amphibia

Why are my water smartweed leaves turning yellow?

It is less common for water smartweed to have yellow leaves, as this plant is quite hardy in its aquatic environment. This symptom usually points to a lack of nutrients or poor water quality, so check your water levels and fertilizer first.

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yellow leaves on a plant
Photo: Trio3D, CC BY-SA 4.0

Check these first

  1. Check the water level to ensure the roots are fully submerged.
  2. Smell the water to see if it has become stagnant.
  3. Look for signs of aphids on the undersides of the leaves.

Likely causes

  1. Nutrient deficiency

    Most likely

    How to tell: The older leaves turn yellow while the veins stay green, or the whole plant looks pale.

    What to do: Add a small amount of aquatic plant fertilizer to the water. Follow the package instructions for your specific container size. Repeat this application every 4 to 6 weeks during the growing season.

  2. Stagnant water

    Possible

    How to tell: The water smells bad or looks murky, and the leaves start yellowing from the bottom up.

    What to do: Change out 50 percent of the water in your container. Ensure the water is fresh and clean. If the plant is in a small bowl, change the water every 3 to 5 days to keep it oxygenated.

Yellow leaves on other plants

Find out what's wrong with your water smartweed

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 yellowing spreads rapidly to the new growth. It is normal for the oldest, lowest leaves to yellow and die back as the plant grows.

Stopping it coming back

Keep the water fresh and provide a balanced aquatic fertilizer during the spring and summer months.

Water smartweed: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your water smartweed 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 the yellow leaves?
Yes, you can snip them off with clean scissors to keep the plant looking tidy. This helps the plant focus its energy on new, healthy growth.
Can too much sun cause yellowing?
Usually no, as this plant loves full sun. If the leaves look bleached or white, however, it might be getting too much intense afternoon heat.

More problems with water smartweed

Back to the water smartweed 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.