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Jack-in-the-pulpit · Arisaema triphyllum

Why are there spots on my Jack-in-the-pulpit leaves?

Spots on your Jack-in-the-pulpit are often a sign of fungal rust, which loves humid, damp conditions. Check the undersides of the leaves for orange or brown powdery patches to confirm this.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Inspect the underside of the leaves for powdery spores.
  2. Check if the plant is crowded by other vegetation.
  3. Look for signs of standing water on the foliage.

Likely causes

  1. Fungal Rust

    Most likely

    How to tell: You will see small, raised orange or reddish brown spots on the leaf surface. These spots often appear after long periods of rain or high humidity.

    What to do: Remove and destroy the infected leaves immediately to stop the spread. Improve air circulation around the plant by thinning out nearby dense foliage. Avoid overhead watering to keep the leaves dry.

  2. Leaf Spot Disease

    Possible

    How to tell: These spots are usually dark brown or black with a yellow halo around them. They tend to grow larger as the infection spreads across the leaf tissue.

    What to do: Prune away the damaged leaves and dispose of them in the trash, not your compost pile. Keep the area around the base of the plant clear of old, decaying plant debris. Apply a copper based fungicide if the infection persists.

Leaf spots on other plants

Find out what's wrong with your jack-in-the-pulpit

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 time to worry if the spots are spreading rapidly to the stems or if the entire leaf is turning yellow. A few small spots late in the season are normal as the plant prepares to go dormant.

Stopping it coming back

Keep the soil surface clean of debris and ensure your plants have enough space for air to move freely between them.

Jack-in-the-pulpit: spots? Check yours with a photo

Every plant is a little different. Take a photo of your jack-in-the-pulpit 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

Will these spots kill my plant?
Usually no, but they can weaken it over time. If you catch it early, your plant will likely bounce back fine next spring.
Should I cut off all the leaves?
Only remove the leaves that show significant damage. The plant still needs its healthy leaves to store energy for next year.

Guides to these causes

More problems with Jack-in-the-pulpit

Back to the Jack-in-the-pulpit 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.