Troubleshooting
Black Mondo Grass problems — and how to fix them
Black Mondo Grass (Ophiopogon planiscapus 'Nigrescens') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Slug and snail damage
Moist, shady conditions encourage slugs, which rasp irregular holes in the foliage. Use iron phosphate pellets or copper barriers; avoid metaldehyde in gardens visited by pets or hedgehogs.
Crown rot in waterlogged soil
Extended waterlogging causes root and crown rot, turning leaves yellow then brown at the base. Ensure free drainage; if symptoms appear, lift clumps, trim affected roots, and replant in improved soil.
Fading foliage colour
Deep black colour fades to brownish-green in full shade or poor soil. Increase light levels slightly or improve soil fertility with compost to restore pigmentation.
Prevent black mondo grass problems before they start
Most black mondo grass issues are care-mismatch, not bad luck. Dial in the basics:
Black Mondo Grass problems — FAQ
Why is my black mondo grass slug and snail damage?
Moist, shady conditions encourage slugs, which rasp irregular holes in the foliage. Use iron phosphate pellets or copper barriers; avoid metaldehyde in gardens visited by pets or hedgehogs.
Why is my black mondo grass crown rot in waterlogged soil?
Extended waterlogging causes root and crown rot, turning leaves yellow then brown at the base. Ensure free drainage; if symptoms appear, lift clumps, trim affected roots, and replant in improved soil.
Why is my black mondo grass fading foliage colour?
Deep black colour fades to brownish-green in full shade or poor soil. Increase light levels slightly or improve soil fertility with compost to restore pigmentation.