Barnhourie Mill, listed category B, is a two-storey building, oblong on plan. A waterwheel is incorporated within the north-east gable wall. The mill was last used in 1910 but the gearing survives and is in reasonable condition. Much of it is of wooden construction. The Miller's Cottage is thought to date from c.1700. It has been converted for use as the residence of the owners.
There are two main areas of woodland. The oldest lies along the eastern boundary and is composed largely of alder species, with some oak and hazel. Reference to the 1st & 2nd edition OS maps shows that woodland was established here in the 19th century but many of the trees are much younger. The burn which flows through the woodland spates readily and understorey planting is avoided, but a dense carpet of wild flowers is established.
On the western boundary of the garden, near the mill pond, Sitka spruce and other conifers have been established since 1962 for shelter. Both this area and that around the burn are reptile and bird sanctuaries with some 83 bird species having been recorded here. Red squirrels are seen here and other visitors include a fox and several types of dragonfly. Pipistrelle bats are resident.
The garden lies to the north of the Miller's House and is divided into named areas by the owners. The Miller's Garden is situated adjacent to the house and is largely lawn, enclosed by beds of dwarf conifers, small-scale shrubs and herbaceous plants. A footpath leads from it through the different areas. Within each, trees and shrubs have been carefully grouped together for their flower, foliage, form and texture. One of the most impressive plants in the garden is a 40 year old specimen of Abies koreana which forms a perfect equilateral triangle when seen in elevation. Some large-leaved Rhododendrons are grown; among them, R. concatenans, and R. campanulatum aeruginosum, which came from Sir Herbert Maxwell's garden at Monreith, Wigtownshire. Other plants are grown in the garden to provide interest beyond April-June. These include Berberis, Cornus, Phyllodoces, Viburnums, Prunus and Kalmia, as well as gentians, including G. asclepiadea and G. sinov- ornata.
The dwarf Rhododendron collection is grouped around a number of knolls in the centre of the garden which are characterised by rocky outcrops. Of particular note are R. repens, R. apodectum Red Form, R. tsariense, and R. recurvoides. They are only a few of some 250 or so varieties grown in the garden which form one of the finest collections of dwarf Rhododendrons in the country.