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Square-stalked St. John's-wort · Hypericum tetrapterum

Why are there bugs on my Hypericum tetrapterum?

It is less common for this plant to have pest issues, but it can happen if the environment is too dry or the plant is stressed. Check the undersides of the leaves and the stems for any signs of movement or webbing.

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pests on a plant
Photo: Jules Verne Times Two, CC BY-SA 4.0

Check these first

  1. Inspect the undersides of leaves for tiny insects.
  2. Look for sticky residue on the stems.
  3. Check for fine webbing near the joints.

Likely causes

  1. Aphids

    Most likely

    How to tell: You will see tiny green or black insects clustering on the new growth and flower buds. They often leave behind a sticky residue called honeydew.

    What to do: Spray the plant with a gentle stream of water to knock them off. If they persist, apply insecticidal soap once a week until they are gone.

  2. Spider Mites

    Possible

    How to tell: Look for fine, silky webbing between the stems and leaves. The foliage may also look speckled or yellowed.

    What to do: Increase the humidity around your plant since these pests love dry air. Wipe the leaves down with a damp cloth and use neem oil if the infestation is heavy.

Pests on other plants

Find out what's wrong with your square-stalked 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

You should worry if the plant starts losing leaves or if the growth looks stunted. A few stray bugs are usually manageable with a quick rinse.

Stopping it coming back

Keep the soil consistently damp and provide good air circulation around the plant. Regularly misting the foliage can also deter mites.

Square-stalked St. John's-wort: pests? Check yours with a photo

Every plant is a little different. Take a photo of your square-stalked 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

Can I use dish soap to kill the bugs?
It is better to use a dedicated insecticidal soap. Household dish soap can sometimes be too harsh and damage the leaves.
Will these pests spread to my other plants?
Yes, pests like aphids and mites can easily move to nearby plants. Isolate your Hypericum until you are sure the infestation is cleared.

Guides to these causes

More problems with Square-stalked St. John's-wort

Back to the Square-stalked 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.