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Marginal wood fern · Dryopteris marginalis

Why does my Marginal wood fern have spots on its fronds?

It is less common for this fern to develop spots, which usually points to fungal issues caused by poor air circulation or wet foliage. Check your plant for damp, stagnant air around the base first.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Inspect the undersides of the fronds for tiny bumps.
  2. Check if the soil surface is staying wet for too long.
  3. Ensure the plant has enough space for air to move around it.

Likely causes

  1. Fungal leaf spot

    Possible

    How to tell: You will see brown or black circular spots that may have a yellow halo. These often appear after the fronds stay wet for too long.

    What to do: Trim off the affected fronds immediately to stop the spread. Improve airflow by moving the plant to a spot with better ventilation and avoid misting the leaves.

  2. Scale insects

    Possible

    How to tell: These appear as small, hard brown bumps on the undersides of the fronds. They suck sap and leave behind sticky residue.

    What to do: Dab each bump with a cotton swab dipped in rubbing alcohol. Repeat this process every 7 days until you no longer see any insects.

Leaf spots on other plants

Find out what's wrong with your marginal wood fern

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 to new growth. It is normal for older, bottom fronds to develop minor blemishes as they age.

Stopping it coming back

Water only at the soil level rather than over the top of the plant. Keep the humidity high but ensure the room has a gentle breeze.

Marginal wood fern: spots? Check yours with a photo

Every plant is a little different. Take a photo of your marginal wood fern 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 a fungicide on my fern?
It is better to focus on cultural fixes like airflow and proper watering. Ferns are sensitive to chemicals, so avoid sprays unless the infection is severe.
Are these spots contagious to my other plants?
Yes, fungal spores can travel through the air or water splashes. Isolate the fern until the spots stop appearing.

Guides to these causes

More problems with Marginal wood fern

Back to the Marginal wood fern 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.