There are still the remnants of the informal designed landscape undertaken in the 1750s which were added to in the early 19th century. The design remained unaltered until the estate was sold in 1922. Today, much of the designed landscape has gone and many of the remaining features are derelict.
In about 1550, Balloch Castle, as Taymouth was then called, was owned by Sir Duncan Campbell, 1st Baronet. According to Burke's peerage he is reputed to have been the 'first Highland laird to turn (his) attention to rural improvements and plant trees and he forced his tenants to do so'. It was his descendant John Campbell, the 2nd Earl of Breadalbane, who succeeded in 1717 and started the alterations to the Castle and the laying out of the grounds. In 1752, he died at the age of 90. His son John, as Lord Glenorchy and later the 3rd Earl of Breadalbane, had taken over the management of Taymouth from his elderly father and is said to have laid out the first design in 1720 and he certainly laid out the second landscape in the 1750s. He married, Amabell de Grey, the daughter and heiress of the 1st Duke of Kent, who had laid out the formal water garden at Wrest Park, Bedfordshire.
In 1720, William Adam produced a plan showing the grand design in which six radiating avenues, each over a mile long, converged on the Castle. Two elaborate gardens with parterres, grass platts and orchards were set on either side of the Castle. To the south of it around the loop of the river, Adam planted an avenue of trees in the shape of a D. This shape was divided by three avenues at angles to the Castle; one extended the central axis through it and the other two subsidiary ones continued lines set up in the two gardens.
On top of the sharply defined terraces on the banks of the river, Adam planted two long avenues of lime trees. These are known as the North Terrace and the South Terrace. In about 1733, this layout appears in a painting called: 'Birdseye view of Taymouth Castle', attributed to James Norie. This painting also shows the renovated Tower Castle with its two flanking pavilions designed by William Adam. In 1739, Jan Griffer (spelt in the accounts as Greffier) was 'paid for making changes to a view of Taymouth'. His changes to the Norie painting can still be discerned. They show the removal of the long radiating avenues and the modification of the gardens to accommodate the pavilions. The park has many more individual trees and the overall design is less formal. General Roy's plan, of c.1750 confirms these changes. It also shows the long avenue leading to the Loch and the outline of the viewing terrace cut into the slope half way up Craig Hill.
In 1754, Thomas Winter prepared another survey of the grounds and by this time all of the formal gardens, the remaining avenue and part of the terrace had been removed. The orchard had been moved to the west of the ridge where the Dairy now stands. The walled garden was also moved to the north-east of the Castle adjacent to the Newhall Kennels. Woodland had been planted on both Drummond Hill and Craig Hill. The North and South Terraces were untouched and so was the D formation of trees to the south of the Castle. Between the 1740s and mid-1750s there are several accounts for the supply of seed and garden equipment. In 1754 there is an account for a box of seed from America which is the same year as Peter Collinson supplied five boxes of seed for 'nobility & gentry of Scotland'. Collinson imported seed of wild plants mainly from the East Coast of America collected by John Bartram. Collinson was also supplying the 3rd Earl's cousin, the Duke of Argyll.
In 1786, a plan of the 'seat of the Earl of Breadalbane' was drawn by George Langlands. This shows a much more polished landscape in the informal style. All the formal planting in the glen has been removed and the entire floor turned into a huge park. The extent of the open space is accentuated by clumps of trees and single specimens. The main road had been moved to halfway up Taymouth Hill and the entrance drive re-aligned. Views of the Castle and most of the follies are shown around the plan and these include, the Octagon, the Fort, Maxwell's Building, Star Seat, Apollo's Temple, Venus' Temple, Aeolus's Temple and the Recess in the Surprise Wall. The Tower, Chinese Bridge and Ladies Mount were noted on the plan but not illustrated.
In 1760, Richard Pococke visited Taymouth and he describes at some length the walk which he took around the pleasure grounds. It must have been a long walk as it included visiting all the buildings shown in Langlands plan and the landscape he described was very similar in concept to that of Stourhead, Hagley Hall and Painshill which had all been started at most only ten years before Taymouth. In 1776, William Gilpin was not as impressed as Pococke, and wrote: 'The whole scene is capable of great improvement: but when we saw it, nothing like taste had been exercised upon it'. Although published in 1796 sometime after his visit, William Marshall, in the 2nd edition of his book on 'Planting and Rural Ornament', describes the 3rd Earl's pleasure ground at some length. He wrote the 'the late Earl .... made Taymouth his principal residence ... and made great alterations in the place; and considering the day in which they were done (near half a century ago, in the early dawn of rational improvements), they remain,....proofs of his superior abilities'. In 1782, John the 4th Earl, aged 20 years old, succeeded his grandfather. In 1789, he commissioned Robert Mylne, the architect to the Duke of Argyll at Inveraray to prepare plans for a new 'chateau'. They were not executed.
But between 1800 and 1834, the 4th Earl transformed the Castle using various architects including Alexander Nasmyth who drew up proposals for another house and a bridge and William Atkinson who was noted for his interest in gardening. In 1831 John was created 1st Marquess of Breadalbane; he died three years later. His son, the 2nd Marquess played host to Queen Victoria and Prince Albert in 1842 during a three day visit to Taymouth and the Castle was exuberantly refurbished by James Gillespie Graham for this visit. In 1866, the Queen returned for a private visit.
Throughout the 19th century, there were changes to the designed landscape; some of the 18th century follies were removed and new ones built in their place; for example, the Venus' Temple was substituted by the Dairy, Maxwell's Building by Maxwell's Temple and the Star Seat by the Star Battery, but it is not known who laid out these changes though William Atkinson designed the replica of Queen Eleanor's Cross as Maxwell's Temple.
In 1823, J.C. Loudon in his Encyclopaedia of Gardening described Taymouth as the 'most magnificent residence in the county. ...... The mountain, lawn and banks of the waters, are richly clothed with wood, through which are led magnificent walks. Of trees, the lime and larches have attained to a great size, and there is an avenue of the former 450 yards in length, scarcely equalled anywhere.'
By the 1st edition OS plan of 1862, there had been several changes to the designed landscape. The kitchen garden had been moved to its present site on the northern banks of the Loch. Several additional drives had been made in the park, and new buildings added, particularly the Dairy Byre, the Monument, the sawmill and Newhall offices and buildings.
In 1862, the 2nd Marquess died and the United Kingdom titles became extinct. The succession to the Scottish Earldom was decided in favour of a very distant cousin, John Campbell, who became the 6th Earl. He died ten years later and was succeeded by his son, Gavin. In 1873, the 7th Earl was created 1st Marquess of Breadalbane and he managed to lose most of his large estate. In 1922, following his death, his nephew inherited and had to sell the Castle and its grounds.
In 1929, the Castle opened as an hotel and the park was laid out as a golf course. During World War II, the Castle was used as a Polish hospital and Nissen Huts were constructed on the lawns between the Castle and the river. The foundations are still there today. In 1950 it became the Civil Defence School run by the Home Office. Recently the lease for a school has terminated and the Castle has been empty for many years. The golf course is still in use today.