By late July the vegetation is becoming mature and plants are concentrating on seed production rather than growth. There are some plants, however, that can ripen seeds quickly and continue to prosper when they flower late.  And some, of course, reproduce by spreading vegetatively and do not have to rely on seed.  In particular, there are several yellow-flowered Composites that show themselves in late summer - that is - plants with flowers like daisies and dandelions in flower structure.

Along the roadside verges the Autumn Hawkbit (Leontodon autumnalis) lines the roadside with a yellow carpet some six inches high. It seems to like the salty environment created by winter salt spreading. Along roadsides and seashores the tall yellow-flowered Perennial Sow-thistle (Sonchus arvensis) stands three feet high with strong prickles on its leaves.  It is the harbinger of autumn for me!  And there is a strong show of yellow from Common Ragwort (Senecio jacobaea). which is poisonous to most animals and a serious pest in the countryside.  Another harbinger of autumn is the Rosebay Willowherb (Chamerion angustifolium) which forms dense colonies here and there adding a mass of pinkish purple colour to the landscape.

In the wet meadow the Meadowsweet (Filipendula ulmaria) dominates to the exclusion of many other plants.

Three of the Caithness lochs have around their margins fairly sweet, muddy wet ground which is the home of the nationally rare Narrow Small-reed (Calamagrostis stricta).  And the margins of another loch has the total world population of the Scottish Small-reed (Calamagrostis scotica) which is quite unique to this one loch in Caithness.  These two grasses flower in August.

On the peaty moorlands the Heather (Calluna vulgaris) comes into flower in early August to colour the hills and moors with purple.  In drier parts of the moor the Bell Heather (Erica cinerea) shows a bigger flower of a more intense purple and in the wetter parts the Cross-leaved Heath (Erica tetralix) shows flowers of a paler pinky purple.  All three species can show white flowers - white heather is a genetic strain which is not uncommon (I would expect to meet it at least once in a day's walk over the autumnal moors).  As the summer fades the iron in the leaves of the moorland plants shows up as a red colouration and the moorland turns a wine-red colour.

A late-flowering species that has appeared this year for the first time in cornfields and set-aside land is the blue flowered Phacelia (Phacelia tanacetifolia).  It is an annual plant introduced from California with seed mixtures. It will be interesting to see if it persists by setting seed.

Common Ragwort (Senecio jacobaea)
is a medium height yellow composite flowered plant with its flowers in tight bunches. It flowers predominantly in late summer and is a dominant part of the scene in August. All the species of Ragwort are poisonous to animals and it is a serious pest in the countryside.

Meadowsweet (Filipendula ulmaria)
has a mass of small fragrant creamy-white flowers. It likes (very) wet ground that is not acid and takes well to the clay areas of Caithness where it spreads and dominates wetter parts.

Heather (Calluna vulgaris)
is the plant that dominates large areas of the drier peatmoors of Caithness. It is a dwarf shrub that flowers during August, its pinky-purple flowers colouring the moors and hills. It has small single leaves (3 mm long) of triangular section. White flowered heather is occasionally found. Heather cannot tolerate long periods of inundation or drying out, so it keeps to the medium-dry part of the moor, being replaced by Cross-leaved Heath in the wetter places and by Bell Heather in the dryer places. It may be attacked by Heather Beetle which can kill out large areas, and it is often set back or killed by burning as part of moorland management. Despite that it could claim to be the most common plant in Caithness.

Bell Heather (Erica cinerea)
grows on peat moors in places which are dry or well-drained. It is a dwarf shrub with larger flowers than Heather and of a deeper purple colour which grow in a cluster which is not at the end of the stem. Its leaves are in bunches of three on the stem. White flowered forms occur.

Cross-leaved Heather (Erica tetralix)
grows on peat moors and bogs in the wettest situations. It is a dwarf shrub with large pink flowers which grow in a cluster on the end of the stem. Leaves are single, but set out in fours round the stem to form a cross. White flowered forms occur.

Rosebay Willowherb (Chamerion angustifolium)
is a tall plant with a large group of bright pink flowers at its top. It invades bare ground and spreads by underground rhizomes and by the dispersal of its seeds on the wind. It is common in roadside verges and disused yards and buildings. Its speed of invasion of bomb sites after World War II earned it the name Fireweed.

Scottish Small-reed (Calamagrostis scotica)
was discovered by the Thurso botanist Robert Dick who called it the Lapland Reed. It occurs in one boggy area near Castletown and has not been found anywhere else in the world. There are thought to be only a few hundred plants. It flowers in August and is capable of growing when totally flooded. The grass is about three feet tall.

Narrow Small-reed (Calamagrostis stricta)
grows around the margins of four lochs in Caithness. It is a rare plant in Britain due to the damage of its habitat in some of its other locations. It is a handsome brown grass around two feet high which flowers in August.

Phacelia (Phacelia tanacetifolia)
is an annual plant, native to California and introduced to Britain in seed mixtures sold to farms, and in special seed mixes designed to suit bees. It is closely related to the Borage family. It has bright blue flowers in a curved "scorpoid". It propagates by seed in its native land.