Pocket Botanist
Check these first
- Inspect the undersides of the leaves for signs of fungal growth.
- Check if the soil stays wet for too long after rain.
- Look for similar spots on nearby native grasses.
Likely causes
Fungal leaf spot
PossibleHow to tell: You will see small, discolored lesions or dark blotches scattered across the blades. These spots often appear after prolonged periods of wet, cool weather.
What to do: Remove the affected blades to stop the spread. Ensure the area has good airflow and avoid overhead watering to keep the foliage dry.
Nutrient deficiency
PossibleHow to tell: The spots may look like yellow or brown flecks appearing on older leaves first. This happens when the soil lacks essential minerals like nitrogen.
What to do: Test your soil to see if it is depleted. Apply a balanced, slow release fertilizer once in early spring if the soil is truly poor.
Find out what's wrong with your cheatgrass
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
If the spots are spreading rapidly across the entire patch, it might be a sign of a more aggressive pathogen. It is normal to see some minor wear on older blades as the season progresses.
Stopping it coming back
Keep the grass in full sun and ensure the soil drains well to prevent moisture buildup.
Cheatgrass: spots? Check yours with a photo
Every plant is a little different. Take a photo of your cheatgrass 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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
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Questions people ask
- Should I use a fungicide on my cheatgrass?
- No, it is rarely worth the effort or cost for this species. Simply improving airflow is usually enough to stop the issue.
- Will the spots kill my grass?
- Usually not, as cheatgrass is very vigorous. It will likely outgrow the damage once the weather conditions improve.
Guides to these causes
More problems with Cheatgrass
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.