Troubleshooting
Porcupine Grass problems — and how to fix them
Porcupine Grass (Miscanthus sinensis 'Strictus') is generally low-drama, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Miscanthus blight (Leptosphaeria)
Fungal disease causing brown lesions on leaf blades and sheaths, especially in humid summers. Remove and bin (do not compost) affected foliage; improve air circulation by dividing congested clumps; avoid overhead irrigation.
Miscanthus mealybug
White waxy mealybugs shelter inside the stems, causing stunted or distorted growth that is difficult to eradicate once established. Monitor in spring when new growth emerges; treat with a systemic neonicotinoid-free insecticide, or remove and destroy heavily infested stems.
Prevent porcupine grass problems before they start
Most porcupine grass issues are care-mismatch, not bad luck. Dial in the basics:
Porcupine Grass problems — FAQ
Why is my porcupine grass miscanthus blight (leptosphaeria)?
Fungal disease causing brown lesions on leaf blades and sheaths, especially in humid summers. Remove and bin (do not compost) affected foliage; improve air circulation by dividing congested clumps; avoid overhead irrigation.
Why is my porcupine grass miscanthus mealybug?
White waxy mealybugs shelter inside the stems, causing stunted or distorted growth that is difficult to eradicate once established. Monitor in spring when new growth emerges; treat with a systemic neonicotinoid-free insecticide, or remove and destroy heavily infested stems.