The site supports an area of semi-natural magnesian limestone grassland, in which blue moor-grass, Sesleria albicans, is the dominant species.

In particular, it has the largest area of the grassland type which is characterised by blue moor-grass, Sesleria albicans, and small scabious, Scabiosa columbaria.

There are two distinct plant communities, the larger of which, dominated by blue moor-grass, Sesleria albicans, and small scabious, Scabiosa columbaria, is known only from east Durham.

Blue Moor-grass can also be found, with Sheep's-fescue and herbs such as Thyme, Salad Burnet and Common Rock-rose.

There is also a small area of equally scarce magnesian limestone grassland, in which blue moor-grass, Sesleria albicans, and glaucous sedge, Carex flacca, are dominant.

The grasslands at Quarrington Hill are typical of the type, being characterised by the presence of blue moor-grass, Sesleria albicans, and small scabious, Scabiosa columbaria.

Gentle slopes on the "Maiden Paps" section support species such as blue moor-grass, common rock-rose, perennial flax and locally uncommon plants such as Frog Orchid, Autumn Gentian and Purple Milk-Vetch.

Although it remains rich in herbs, the characteristic features of magnesian limestone grassland were lost during the translocation: blue moor-grass is uncommon, while coltsfoot, Tussilago farfara, and field sow-thistle, Sonchus arvensis, which entered the grassland during translocation, persist.

The remaining two communities (CG8 and CG9) are characterised by the presence of Blue Moor-grass (Sesleria caerulea), both of which are localised in northern England and do not fall neatly into either of the two groups described above.

The site has an important expanse of primary magnesian limestone grassland, in which the dominant blue moor-grass, Sesleria albicans, is associated with species such as quaking grass, Briza media, glaucous sedge, Carex flacca, and meadow oat-grass, Avenula pratensis.

Blue moor-grass, Sesleria albicans, is abundant, and there is a rich assemblage of species characteristic of calcareous soils, such as quaking grass, Briza media, meadow oat grass, Avenula pratensis, glaucous sedge, Carex flacca, and fragrant orchid, Gymnadenia conopsea.