Should I cut off the yellow leaves?

Yes, you can snip off yellow leaves with clean scissors. This keeps the plant looking tidy and allows it to focus energy on healthy growth.

Is yellowing always a sign of death?

Not at all, it is just the plant's way of telling you it is unhappy. Adjusting your watering habits usually brings it back to health quickly.

Black horehound: yellow leaves, causes and fixes

Check these first

Stick your finger one inch into the soil to check for moisture.
Lift the pot to see if it feels heavy with water.
Inspect the drainage holes for any blockages.

Likely causes

Overwatering
Most likely
How to tell: The lower leaves turn yellow and feel soft or mushy to the touch. The soil stays damp for more than 14 days.
What to do: Stop watering immediately and let the top 2 inches of soil dry out completely. Ensure your pot has drainage holes and never let the plant sit in a saucer of standing water.
Nutrient Deficiency
Possible
How to tell: It is less common for this plant to yellow from hunger, but it happens when the soil is depleted of nitrogen. The older leaves turn pale yellow while the veins remain green.
What to do: Apply a balanced liquid fertilizer diluted to half strength once a month during the growing season. Avoid overfeeding, as this can burn the roots.

Yellow leaves on other plants

Find out what's wrong with your black horehound

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.

When to worry

A single yellow leaf at the very base of the plant is often just an old leaf dying off. Worry if multiple leaves yellow at once or if the stems start to wilt.

Stopping it coming back

Follow the 7 to 14 day watering schedule strictly based on the dryness of the top inch of soil. Use a well draining potting mix to prevent water from pooling around the roots.

Black horehound: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your black horehound 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.

Get the app · Or check it from a photo now, free

Questions people ask

Should I cut off the yellow leaves?: Yes, you can snip off yellow leaves with clean scissors. This keeps the plant looking tidy and allows it to focus energy on healthy growth.
Is yellowing always a sign of death?: Not at all, it is just the plant's way of telling you it is unhappy. Adjusting your watering habits usually brings it back to health quickly.

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