The present designed landscape was established in the late 18th century and was improved in the latter half of the 19th century. There are no known landscape designers.
The Mercer family of Meikleour and Aldie is one of the oldest in Perthshire. Records of its links with Meikleour go back to 1392 when it was granted the Barony. The Mercers became allied to the Nairne family, whose estate extended from Stanley to Bankfoot, by the marriage of heiress Jean Mercer and the Hon Robert Nairne. The Beech Hedge was planted by them in c.1746.
Jean Mercer, granddaughter of Robert Nairne inherited Meikleour in 1790. She married George Keith Elphinstone, son of the 10th Lord Keith, who became Admiral Sir George Keith Elphinstone, Viscount Keith. They purchased the estate of Tulliallan which became their main home. Meikleour, however, was still used; the house was altered and considerable improvements were made to the Meikleour estates. Their daughter, Margaret, married Count de Flauhault de la Bellarderie in 1817 and, six years later, she inherited Meikleour on the death of her father. She also inherited the title of Baroness Keith and, in 1837, became Baroness Nairne. Her daughter Emily married the 4th Marquis of Landsdowne in 1843. The present house was commissioned by the Marquis and Marchioness and built between 1869-70. Extensive improvements were undertaken at this time throughout the estate.
Meikleour House is now the home of the 8th Marquis of Lansdowne who has made considerable improvements to the policies and has a keen interest in the gardens.
Meikleour House, listed category B, was designed by David Bryce between 1869-70; it incorporated an earlier house built in 1734. This was a simple rectangle with a sculptured pediment (which can still be seen on the garden front). The Sundial, listed category B, is vase-shaped with a brass dial dated 1776. The Old Gatepiers, listed category B, are probably 18th century. Meikleour Stables are listed category C(S) and incorporate a door pediment dated 1734. The rest of the building is late 18th century or early 19th century with 1870 additions. Recently it has been converted into dwellings. The Bridge of Isla was built between 1794-96 and is listed category A. The South Lodge is now cut off from the main policies by the new road alignment.
The 1st edition OS plan indicates the scale and size of the original design. The park lies to the east and north of the house. In the east park, the double avenue of beech, sycamore and limes framing the view to Dunsinnan Hill used to be clipped to create a 'grand sylvan gothic arch'. Recently some of the trees have been replanted. The parks were 'greatly improved' during the 1870s and most of the woodland clumps of mainly beech, lime, sweet chestnut and sycamore belong to this period; several conifers were also planted including Wellingtonias and silver spruce (Picea alba). Most of the park fields are in pasture and are grazed; a few of the parkland trees also remain. The sweeping east drive curving under Craw Law Wood is likely to have been built early in the 19th century. A drive sweeps through the north park to Meikleour village. The new kitchen garden was added to this area of parkland c.1890; access to it was gained by a spur off the north drive.
All the woodland clumps within the park have been planted for amenity and contain a mixture of broadleaved trees and conifers. The Craw Law Wood was replanted c.1850. The magnificent beech hedge, for which Meikleour is renowned, was planted in 1746; it runs along the A93 for about three quarters of a mile. The trees have reached a height of over 100' and the hedge is still cut about once every 7/8 years. Methods of cutting it have always exercised the ingenuity of the owners and staff and various machines have been used. The extensive North Wood and South Wood lie to the north of Meikleour village but have never been considered to be part of the policies.
The garden runs along the north bank of the Tay and has been made under the shelter of an early 19th century mixed woodland. Rhododendrons and other 'exotic' shrubs are well established along the lower terrace. Since 1973, the 8th Marquis has designed and created a new garden to the south along the riverbank. A pond has been made and the stone for the walls and steps has been taken from the former ha-ha wall in the park between the kitchen garden and the village. The steep banks to the terrace are planted with some unusual trees and shrubs, particularly species of Acer and Sorbus. The walk along the steep bank above the terraces provides attractive views into the new garden, whilst other walks meander through the plantings.
The garden to the east of the house is largely lawn, ornamented by two magnificent sweet chestnut trees which possibly date back to the 1650s. The sundial was recently moved to its present position and it is surrounded by pinks, thyme, and other herbs. To the west of the house on the mount where the doocot stood is a delightful woodland glade recently planted by the 8th Marquis, with shrubs including roses, and Acers, Sorbus and other ornamental trees including a hybrid lime (Tilia tomentosa x petiolaris) and a magnificent Douglas fir (Pseudotsuga menziesii) stand near the drive. The mount has been planted up with shrubs. Older clumps of Rhododendrons mark the path to the stables. There are long walks along the river where many evergreen shrubs have been planted such as yew, holly and Rhododendrons with larch, oak and beech providing the canopy.
The original walled garden was sited near the stables. A new kitchen garden was constructed in c.1890. The vineries and other greenhouses were specifically designed for the new garden and the glasshouses were heated by gas converted from coke at the gas works on site. A woodland walk was made around the garden and a ha-ha built along the boundary with the park to provide views across it. The kitchen garden continued to be used until World War II. A new kitchen garden was designed by the present owner in the 1960s to the north of the house. It is enclosed by walls and grows fruit and vegetables. Honeysuckle, roses and Clematis grow up the house, and flower borders for all seasons have been planted along its north side.