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Slender St. John's Wort · Hypericum pulchrum

Why are my Hypericum pulchrum leaves turning yellow?

It is less common for this plant to have yellow leaves, which usually happens due to overwatering or poor drainage. Check the soil moisture first to see if the roots are sitting in water.

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

Check these first

  1. Feel the top inch of soil for moisture.
  2. Inspect the drainage holes to ensure they are not blocked.
  3. Check the base of the stems for any signs of mushiness.

Likely causes

  1. Overwatering

    Most likely

    How to tell: The leaves turn yellow starting from the bottom of the plant and may feel soft or mushy. The soil stays wet for more than 10 days.

    What to do: Let the top inch of soil dry out completely before watering again. Ensure your pot has drainage holes so excess water can escape.

  2. Nutrient deficiency

    Possible

    How to tell: The leaves turn a pale yellow while the veins remain green. This often happens if the plant has been in the same pot for a long time.

    What to do: Apply a balanced liquid fertilizer diluted to half strength once a month during the growing season. Repot the plant into fresh, well draining potting mix if it has been over a year.

Yellow leaves on other plants

Find out what's wrong with your slender st. john's wort

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

It is normal for the oldest, lowest leaves to yellow and drop as the plant grows. Worry if the yellowing spreads rapidly to newer growth or if the stems feel soft.

Stopping it coming back

Stick to a consistent watering schedule and only water when the top inch of soil is dry.

Slender St. John's Wort: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your slender st. john's wort 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 help the plant look better. This also allows the plant to focus its energy on healthy growth.
Can too much sun cause yellow leaves?
Yes, if the plant gets too much direct, harsh sun, the leaves can bleach to a pale yellow. Move the plant to a spot with partial shade.

More problems with Slender St. John's Wort

Back to the Slender St. John's Wort 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.