The sandy areas by the sea warm up quickly.  The flora of the dunes is not rich, but the areas of fine grass behind the dunes develop a diverse range of interesting and colourful flowers including the Wild Pansy. The clifftops have a heath turf of short tough plants which includes the very rare Scottish Primrose and the very common Sea Pink.

Inland the heavy cold peaty ground warms less quickly and plants are slow to emerge from their winter state.  But the sun and warmer winds bring flowers to the Great Sundew as its new leaves make ready to catch insects for its nourishment.  In the less peaty places the Common Sedge shows its black flowers and in a secret place along the banks of the Thurso river the Holy Grass is amongst the first of the grasses to bring out flowers.

The cultivated fields have been ploughed, harrowed and sown.  The weed seeds hurry to germinate and grown in competition with the crop and the Wild Pansy and the Charlock are two of the most prominent.

Charlock (Sinapis arvensis)
The ploughed fields spring to life, not only with crops, but also with agricultural weeds.  Some are very colourful and a common and noticeable one is Charlock, with its yellow four-petalled flowers.  It dies back in the winter to a brown tangle of stalks and seeds which provide wintering birds with cover and food.

Great Sundew (Drosera anglica)
On the peatmoors and acid wetlands the summer is slow to start since the soil is heavy and cold. Even when it has warmed the conditions are not attractive to most plants.  Some specially adapted species prosper and one of these is the Great Sundew. It is able to make up for the lack of nitrogen in the soil by catching and digesting insects. Its leaves are covered in sticky hairs which catch small insects; the hairs then exude a digestive juice which dissolves the soft parts of the insect.  The juice can then be reabsorbed into the leaf. It is less common than the Round-leaved Sundew and prefers a wetter part of the peat moor or the shallow margin of a loch.

Common Dog-violet (Viola riviniana)
This is the most common purple violet in Caithness.  It likes drier places in grassland and shady nooks in woodland or rough. It has heart-shaped leaves which distinguish it from the other common purple violet, Viola palustris (which has round leaves).

Common Sedge or Black Sedge (Carex nigra)
Sedges are an important part of the grassy flora of Caithness.  Many sedges have the male and female flowers separated into spikes, as in the common sedge of this picture.  The male flowers are at the top, with yellow stamens which carry the pollen. The female flowers are lower and have white styles which protrude from the “glume” - the scale which protects the flower.  Later in the season the nut will develop underneath the glume.  The common sedge can be found in the sweeter wet places in Caithness - in burns and boggy hollows on the clay ground.
 

Hawthorn (Crataegus monogyna)
This is naturally a small tree which can be found up to 5 metres high in Caithness.  It is commonly planted as a hedgerow and in June the flowers - most commonly white, but sometimes pink - line our roads. I suspect that none of it is native to Caithness, but introduced. In exposed places it becomes wind-pruned, being killed off on the windward side and growing on the sheltered side, to be come a very lop-sided shape.

Holy-grass (Hierochloe odorata)
The first accepted finding of Holy-grass in Britain was by Robert Dick of Thurso around 1854 (the bashful man had found it twenty years earlier but not told anyone). It is now known from Orkney, the Western Isles, south-west Scotland, Northern Ireland and a few other scattered places, but remains a rare plant. In Caithness it occurs in quantity on the banks of the Thurso river, further south than the original site reported by Dick.

Wild Pansy (Viola tricolor)
On the dunes, Sandside, Dunnet and Keiss and other seaside sands, is Viola tricolor ssp. curtisii as shown in the picture. It differs little from the agricultural version Viola tricolor ssp. tricolor. Which can be seen amongst the crops in a cultivated field.  It flowers in early summer.

Common Bird’s-foot-trefoil (Lotus corniculatus)
On well-drained grassy banks and bare rocky places the bright yellow pea-flowers of the Bird’s-foot-trefoil are to be seen in early and mid summer.  The leaves are three-lobed. Later the fruits develop, revealing how the plant gets its name, for each is long and thin, the shape of a bird’s toe and they splay out to make the shape of a bird’s foot. It is a leguminous plant - i.e. it has nodules on its roots that capture nitrogen from the air and enrich the soil by making nitrate.

Scottish Primrose (Primula scotica)
This tiny plant is a miniature beauty.  It is one to two inches high (30 to 50mm) with flowers only a quarter inch diameter (6mm). It grows only in Scotland, indeed only in Caithness, Orkney and North Sutherland. First found on Holborn Head in 1725, there are still some present there.  Indeed there are colonies scattered around the Caithness coast growing in short grass on clifftops and in the machair-like fine grassland at the back of the dunes at Dunnet and Keiss.  It can be seen at Sandside Head, Dunnet (ask the Wildlife Ranger ), Keiss Links, Noss Head and many other places.
 

Red Campion (Silene dioica)
The rough grassy areas and grassy cliffs become alive with the bright colour of Red Campion in the middle of May and the flowering continues well into the summer.  While most plants are red flowered, white ones occur - there is a good colony near the mausoleum on the Isle of Stroma - and with the white comes some pink individuals.

Thrift or Seapink (Armeria maritima)
Thrift is very common around our coast. It grows on grassy cliffs, in crevices in rocks in the cliff face and rocky shore, on harbour walls, and in muddy shores.  It even grows on roadsides where the winter salt makes the soil suitable and on the rocky parts of mountains.  A most successful plant! Flower colour varies from pale pink to deep purple and the form of the plant varies from a straggling tangle to a tightly compacted mound, depending on exposure, light and the nature of the substrate.