Sir Harold Hillier Gardens and Cadland

12 June 2019

(left to right) Sue Tymon, David Jewell, Roy Lancaster, Gilly Drummond

Sir Harold Hillier Gardens
The Sir Harold Hillier Gardens consist of 180 acres planted with 42,000 trees and shrubs and includes about 12,000 species. It has the largest collection of hardy trees and shrubs in the world and currently holds 14 national plant collections, including oaks, pines, metasequoia, cornus, hamamelis and cercidiphyllum (katsura).  It offers a stunning display of colour in any season.

​​The Gardens are located three miles from Romsey in Hampshire and were founded in 1953 by the famous nurseryman, Sir Harold Hillier, when he acquired Jermyns House and its grounds. He greatly expanded its collection of specimen trees from around the world and, in 1977, donated the arboretum to a charitable trust, managed by Hampshire County Council and dedicated to horticulture, conservation, education and recreation.

​There have only been six curators of the Gardens and MPG members were fortunate to be guided by the current curator, David Jewell, and accompanied by the first curator, Roy Lancaster OBE, well-known for broadcasting, writing, and plant-finding expeditions.

David Jewell welcomed members, noting that their interest in dry gardening was very relevant to recent challenges for the Gardens. In April and May, rainfall had been half of the usual average and trees and shrubs had started to show the effect of dry conditions.  Fortunately, heavy rain in the previous 24 hours had brought some vital support. Development plans for the Gardens included the Frontier Project which would be based on dry, self-sustaining planting. In 2018, the Gardens had attracted 245,000 visitors so there were also plans for key infrastructure improvements to provide for increasing numbers.

​David Jewell began the tour with a comparison of three oak trees collected by Sir Harold Hillier and Roy Lancaster. The first tree was a Quercus castaneifolia which is one of 600 ‘champion trees’ in the Garden. Champion trees are individual trees which are exceptional examples of their species because of their size, age, rarity or historical significance. The Tree Register of Britain and Ireland ( has details of more than 4,000 champion trees online and over 150,000 trees in total.

Quercus castaneifolia
Quercus rhysophylla
Quercus macranthera

The next oak mentioned by David Jewell was Quercus macranthera the Persian or Caucasian Oak, it was one of Sir Harold Hillier’s favourite trees and planted about 40 years ago. The third oak was Quercus rhysophylla, the loquat oak, collected by Sir Harold in 1980 from Monterrey Falls, Mexico.  It is evergreen and drought tolerant.  David noted that the vigorous growth of this tree illustrated a common problem for the Gardens.  The Q. rhysophylla was very attractive and could reach 60 feet but only if one or both specimen trees on either side were removed.

David Jewell had planned a walk through the Gardens, illustrated by bunches of foliage and flowers at intervals, and pointed out planting and plants of interest.

David Jewell with Cornus capitata ‘Highdown’
Paeoni lactiflora ‘Jan van Leeuwen’

Cornus capitata ‘Highdown’ – A stunning, white flowering dogwood requiring acid to neutral soil.

Paeoni lactiflora ‘Jan van Leeuwen’ – One of many excellent peonies in a border of intersectional hybrids and others.

Wisteria sinensis and floribunda

Wisteria sinensis and floribunda – a sponsored installation of 2.4m high poles, 1.5m apart, using trained spur pruning to produce columns “dripping with flowers”.  David Jewell noted that, intriguingly, Wisteria floribunda spirals clockwise while sinensis spirals anticlockwise.

Centenary border

Centenary border
​Sir Harold Hillier first planted the border in 1964 to celebrate the 100th anniversary of his grandfather starting the family business. It was then a series of semi-circular bays, each the length of a cricket pitch, filled with roses and other shrubs. By 2010, the border was overgrown and dense and it was decided to redesign it for the 21st century. The new border is 250 metre long with 30,000 plants and was the longest in the world until Kew opened its 320 metre border in 2016.

Eryngium ‘Blue Waves’

Catalpa fargesii – named for Père David Farges, the French naturalist and missionary to Szechuan, seeds were introduced by Henry Wilson to the UK in the early 1900s. David demonstrated the beautiful pink flowers which cover the tree in early summer.
Styrax japonica – at the back of the border but pointed out as an elegant shrub.

​Magnolia sieboldii ‘ Colossus’ – Sir Harold Hillier collected this remarkable specimen from Mexico.
Sorbus cuspidata – The Himalayan whitebeam next to Jermyns was also collected by Sir Harold Hillier.
​Digitalis lutea – the yellow foxglove contrasts well with the slate base of the flowerbed.
Metasequoia standing on the left of Jermyns, introduced by Sir Harold Hillier and one of the first ​Metasequoia to reach the UK.

The sculpture is flanked on three sides by three silver birches:

Betula utilis subsp. utilis
Betula utilis Jacquemontii ‘Grayswood Ghost’
Betula calcicola

New Frontier Project

Standing on the site of the project, David explained to members the plans to seek investment for a three-phase project to expand the Gardens. He pointed out a map illustrating how the site near Jermyns will become a new development addressing the issue of climate change and providing a new route for visitors through the gardens. The landscape designer for the project is Tom Stuart-Smith.

The intention is to push the boundaries of plant hardiness and adaptability to a changing climate. Planting in Phase One will use crushed stone with root trainers and very limited watering. This will build upon past experimentation into dry gardening by both Beth Chatto and Sir Harold Hillier.

Each continent will be represented and will also feature pergolas with beams 30 cms thick to support climbing plants which are currently underrepresented in the Gardens. Phase Two and Three will include an ambitious meadow area, which could be Chinese or Japanese, and woods of the world, including Japan, North America and Europe.

​From the Frontier Project site, MPG members passed a joint RHS/Hillier trial of the genus Hypericum.  David noted that to date the Gardens have assessed 135 species for hardiness, habit, quality and continuity of flowering and foliage, overall impact and resistance to pest and disease. The objective is to clarify species and identify potential AGMs.

Toona sinensis ‘Flamingo’ – sunlight catching the pink foliage of these beautiful trees from China, E and SE Asia produced a special moment of the visit. David mentioned that the young leaves or shoots grown like cress are used as a salad.
The route for the rest of the visit led down to the lake and back to Jermyns.

Toona sinensis ‘Flamingo’

axodium distichum – by the water there is a beautiful foliage tree, which is a deciduous conifer, known as the bald cypress or swamp cypress throughout the SE United States.

​Acer sempervirens – the Cretan Maple, is another lovely specimen, with glossy, evergreen leaves, assisting it to be drought resistant and heat tolerant. The fruit is a double samara with two red winged seeds.

Acer sempervirens
Fuschia magellanica var. molinae – the Maiden’s blush fuschia at the back of Jermyns.

Cadland Gardens
Members then drove south toward the Solent, turning right just before Calshot to find the Cadland estate.

Cadland Gardens consist of about 27 acres which were originally landscaped by Capability Brown. MPG member, Gilly Drummond warmly welcomed everyone to the Gardens and the veranda of Cadland House, which provided a magnificent view over the Solent to the Isle of Wight. Gilly explained how the Drummond family came to this place almost 250 years ago and how the foreshore below the house was believed to be where Cerdic, the first king of Saxon Wessex, landed in about 495 AD.

The Drummond family is thought to have originated in Scotland in the 11th century from amongst noblemen accompanying Edgar Aetheling, the last of Cerdic’s line, who took refuge in Scotland after the Norman conquest. The Drummonds were members of the Scottish aristocracy and prominent Jacobites until 1746, when William, Viscount Strathallen died at Culloden. However, his sons, Robert and Henry, joined their uncle Andrew in London, who, in 1717, had founded Drummonds Bank. The bank was highly successful and, in 1772, Robert acquired the manor of Cadland, near Fawley, and invited Henry Holland to build a new house and Capability Brown to landscape the gardens.

Unfortunately, the 18th century house was demolished in 1953 following the compulsory purchase of much of the estate to build the Fawley Oil Refinery. The current Cadland House is an elegant modern home, rebuilt in 1934 after a fire in 1916 destroyed the original ‘fishing cottage’ designed by Holland and its Victorian additions. Gilly explained that, for some years, the Drummond family have been restoring much of the original planting, based on plants introduced by 1780, and rebuilding Brown’s landscaping based on the original plans.

Members were divided into two parties, one to visit the pleasure grounds, clumps, views and vistas, and one to see the two walled gardens. The following photographs give an idea of the walled gardens and Victorian greenhouses.

Judith and Jonathan Whiticar

Photos: Jonathan Whiticar, Sue Tymon