Purple Moor-grass

Management of purple moor-grass is a challenge for conservation organisations around Europe. It is a natural part of the European landscape. However it can often outcompete rarer species on heathlands and bogs. Therefore its growth has to be managed to preserve biodiversity.

What is it?

Latin name Molina Caerulea, purple moor-grass is a flowering grass that grows in damp acid soils such as heaths, bogs and moors. It Flowers between July and September before turning brown in the late autumn. It can reach heights of up to 90cm.

Why do you need to remove it?

Purple moor-grass often dominates heathland and bog sites. This is because it is able to make more effective use of excess nitrogen in the soil. This allows it to out-compete other plants where the soil has received excess nitrogen.  

Excess Nitrogen occurs when the Nitrogen Oxides produced by car exhausts, industry, and agriculture becomes embedded in the soil. The subsidence of peat due to drainage also increases the concentration of nitrogen. Therefore many drained peatland areas have excessive quantities of nitrogen in the soil.

The moor-grass grows so well in these conditions that it can threaten the biodiversity of conservation sites. As well as outcompeting other plants, as it grows in dense tussocks it does not provide a good habitat for many protected insects, including butterflies, grasshoppers and ants.

How can you better manage it?

In part this can be prevented by raising the water level and halting the degradation of the peat. At our trial site De Nol in the Grenspark, this will be the first step to better management. However, where there has been substantial degradation over a period of years (such as in De Nol), the cutting will need to go on over the long term.

Mechanical harvester removing moorgrass

Mechanical cutter removing moor-grass on wet ground. 

What can you make with it?

The Moor-grass can be used for a variety of purposes once it has been cut. The simplest option is to create compost. However as a fibrous plant it can be used for many things.  Natuurpunt are also exploring other options, such as the creation of grass paper and cardboard. These have already been trialled. Another option is the creation of bio-insulation materials.

What are you doing in CANAPE?

Within the CANAPE project we are;

  • Management of Moor-grass to help secure the biodiversity of De Nol in the Grenspark.
  • Trialling the production of useful products from Moor-grass.