Troubleshooting
Purple Moor Grass problems — and how to fix them
Purple Moor Grass (Molinia caerulea 'Moorhexe') 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.
Slow establishment
Molinia grasses are slow to establish and may appear weak in their first season. Do not over-feed or over-water in response — patience is required. Growth accelerates in years two and three once the root system is settled.
Alkaline soil decline
Plants grown in chalky or alkaline soils develop chlorosis (yellowing leaves) and poor vigour. Test soil pH and acidify with sulphur chips or plant in raised beds with ericaceous compost mixed into loam if your native soil is alkaline.
Self-seeding nuisance
In favorable conditions, Moorhexe can self-seed modestly. Deadhead flower stems after the main display if unwanted seedlings are a concern, or allow to naturalise in wilder parts of the garden.
Prevent purple moor grass problems before they start
Most purple moor grass issues are care-mismatch, not bad luck. Dial in the basics:
Looking for purple moor grass in general rather than its problems? Read the full purple moor grass care guide — light, water, soil and feeding.
Purple Moor Grass problems — FAQ
Why is my purple moor grass slow establishment?
Molinia grasses are slow to establish and may appear weak in their first season. Do not over-feed or over-water in response — patience is required. Growth accelerates in years two and three once the root system is settled.
Why is my purple moor grass alkaline soil decline?
Plants grown in chalky or alkaline soils develop chlorosis (yellowing leaves) and poor vigour. Test soil pH and acidify with sulphur chips or plant in raised beds with ericaceous compost mixed into loam if your native soil is alkaline.
Why is my purple moor grass self-seeding nuisance?
In favorable conditions, Moorhexe can self-seed modestly. Deadhead flower stems after the main display if unwanted seedlings are a concern, or allow to naturalise in wilder parts of the garden.