Troubleshooting
tall purple moor grass problems — and how to fix them
tall purple moor grass (Molinia arundinacea) 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 on emerging shoots
Young spring shoots are attractive to slugs. Apply iron phosphate pellets or use physical barriers around the clump base in early spring. Once growth is established and culms harden, damage risk is minimal.
Leaning or floppy culms
Caused by excessive shade, over-rich soil, or strong exposure. Ensure full sun, avoid heavy feeding, and position the plant with some shelter from the worst winds without full shade. Culms self-right to some extent as the season progresses.
Slow establishment on dry or alkaline soils
Molinia is intolerant of drought, particularly in its first two seasons. Amend alkaline soils with composted bark or acidic mulch, water regularly during dry spells, and avoid planting into excessively chalky ground.
Prevent tall purple moor grass problems before they start
Most tall purple moor grass issues are care-mismatch, not bad luck. Dial in the basics:
tall purple moor grass problems — FAQ
Why is my tall purple moor grass slug and snail damage on emerging shoots?
Young spring shoots are attractive to slugs. Apply iron phosphate pellets or use physical barriers around the clump base in early spring. Once growth is established and culms harden, damage risk is minimal.
Why is my tall purple moor grass leaning or floppy culms?
Caused by excessive shade, over-rich soil, or strong exposure. Ensure full sun, avoid heavy feeding, and position the plant with some shelter from the worst winds without full shade. Culms self-right to some extent as the season progresses.
Why is my tall purple moor grass slow establishment on dry or alkaline soils?
Molinia is intolerant of drought, particularly in its first two seasons. Amend alkaline soils with composted bark or acidic mulch, water regularly during dry spells, and avoid planting into excessively chalky ground.