In the research for New Trees many arboreta were visited, to observe and make notes on the trees, and information was also obtained in correspondence and coversation with owners and curators. This process continues for Trees and Shrubs Online. To enable comparison of growing conditions among major collections climate and environment data is presented below. This information has been reproduced from New Trees and users are encouraged to check online for up to date contact information, and to bear in mind that in a period of rapid climate change many of the meteorological records will have changed since this data was assembled in 2009.
Harvard University and the City of Boston:
125 Arborway, Boston,
Massachusetts 02130, USA
The Arnold Arboretum comprises 107 ha of varying terrain, from low-lying, marshy areas to several distinct hills and ridges. The soils are also considerably variable, including silts, sands and clays. The arboretum was founded in 1872 when the President and fellows of Harvard College became trustees of part of the estate of a wealthy New England merchant, James Arnold. Charles Sprague Sargent was appointed director, and with landscape architect Frederick Law Olmsted, developed the road and pathway system and delineated the grounds, on land in the Jamaica Plain area of Boston previously given to Harvard by Benjamin Bussey. Specialist collections of Acer, Carya, conifers, Fagus, Magnolia, Quercus, Rosaceae. Catalogue available online.
Altitude 15–79 m. Zone 6. Rainfall 1102 mm. January mean temp. 1.3 °C; July mean temp. 19.3 °C, July mean max. temp. 23.1 °C.
The Forestry Commission: Bedgebury Pinetum, Goudhurst, Kent TN17 2SL, UK
Started in 1925 as a partnership between the Forestry Commission and Kew, since 1965 the Pinetum has been managed by the Forestry Commission. It comprises 130 ha of gently rolling landscape with lakes, streams, a very rich native flora and fauna, and one of the most important conifer collections in the world. In addition to the botanical collection there are old forestry trial plots of various species. There are nine different soil types, pH 3.5 to 6.5 (average 4.5), and they are particularly nutrient deficient. The emphasis has always been on conifer species and cultivars but there are also fine examples of broadleaf trees and shrubs. Conservation of conifers has become important, and many of the new plantings are from collections from the wild by Bedgebury staff. National Plant Collections of Chamaecyparis lawsoniana cultivars, ×Cuprocyparis leylandii, Juniperus, Thuja, Taxus. A list of taxa cultivated is available online (see www.bedgeburypinetum.org.uk).
Altitude c.130 m. Zone 8–9. Some meteorological data from Cranbrook, Kent (92 m) (Weatherbase 2008). Rainfall 680 mm. January mean 3 °C, absolute min. –18.4 °C (January 1940) (Bedgebury records); July mean 16 °C, July mean max. 21 °C, absolute max. 32 °C (in past five years).
State-owned: Domein van Bouchout, Nieuwelaan 38,
B-1860 Meise, Belgium
This 92 ha estate has gently undulating terrain with two small lakes and a stream forming a valley through the centre. The soil is an alkaline loam over clay. Belgium’s previous national botanic garden was in Brussels, but increasing urbanisation limited growth of the garden, so in 1938 the Belgian government purchased the current site, the Bouchout estate in Meise, from the royal family. In 1939 the first buildings and greenhouses were set up and the first plants were moved from Brussels to Meise. Specialist collections of Acer, Magnolia, Quercus. Catalogue available online (www.br.fgov.be/RESEARCH/COLLECTIONS/LIVING/LIVCOL/index.html).
Altitude 33 m. Zone 8. Rainfall 780 mm. January mean 2.6 °C, January mean min. –0.3 °C, absolute min. –20.2 °C (1981); July mean 17.1 °C, July mean max. 21.6 °C, absolute max. 38.8 °C (June 1947).
Royal Botanic Garden Edinburgh:
Dunoon, Argyll PA23 8QU, UK
Benmore comprises the south-, east- and west-facing slopes of the Eachaig valley in western Scotland, with acid to strongly acid soil (to pH 3.9). Tree plantings date back to the 1820s; the famous avenue of Sequoiadendron giganteum was planted in 1863. Since becoming a regional garden of the Royal Botanic Garden Edinburgh in 1928, the collection’s diversity and wild-origin status has risen. Plants from the Sino-Himalaya and temperate rain-forest regions of the world have been targeted, resulting in phytogeographic plantings from Bhutan, Chile, Japan and Tasmania. Specialist collections of Abies, Cephalotaxus, Picea, Nothofagus, Rhododendron. Catalogue available online.
Altitude 15–137 m. Zone 8. Rainfall 2400 mm. January mean min. 1.9 °C, absolute min. –13.9 °C (2006); July mean max. 21.9 °C, absolute max. 29.6 °C.
Chicago Horticultural Society:
1000 Lake Cook Road, Glencoe, Illinois 60022, USA
Tel. +1 (0)847 835 5440, Website www.chicagobotanic.org
Situated in northern Cook Co., the Chicago Botanic Garden comprises 156 ha of gently rolling hills. Half of it is landscaped and the rest includes natural woodland, lakes and the Skokie River. Soils are primarily heavy silt-clays. Originally leased by the Chicago Horticultural Society in 1965, the garden was opened to the public in 1972. Landscaping began in 1967 and continues to this day. There is an extensive collection of cultivated, native and aquatic plants. Specialist collections of Amelanchier, Cornus (non-bracted), Ginkgo, native Quercus, Salix, Thuja plicata. Catalogue available online; printed copies available at the Plant Information Desk (Visitor Center) and in the Library (Regenstein Education Building).
Altitude 200–210 m. Zone 5. Rainfall 930 mm. January mean –4 °C, January mean min. –8 °C, absolute min. –27 °C (January 1982); July mean 24 °C, July mean max. 28 °C, absolute max. 41 °C (July 1995).
Royal Botanic Garden Edinburgh:
Stobo, Peebles, The Borders EH45 9JU, UK
This garden extends over 25 ha of north-facing slopes above the River Tweed, on soils derived from glacial drift, so stony, free-draining and acidic. Dawyck has benefited from over 300 years of sustained tree planting, including many first introductions. The historic tree collection includes many fine conifers from North America and Asia (particularly China and Japan). Dawyk became a regional garden of the Royal Botanic Garden Edinburgh in 1978, and has many new plantings of shrubs, deciduous trees and conifers, particularly from cool temperate areas of the northern hemisphere. Specialist collections of Betula, Cotoneaster, Sorbus, Spiraea. National Plant Collections of Larix, Tsuga. Catalogue available online.
Altitude 200–210 m. Zone 8. Rainfall 1000 mm. January mean 3.4 °C, January mean min. –0.6 °C, absolute min. –19.2 °C (December 1995); July mean 14.6 °C, July mean max. 19.8 °C, absolute max. 29.8 °C (July 2006).
Royal Botanic Garden Edinburgh:
20A Inverleith Row, Edinburgh EH3 5LR, UK
Tel. +44 (0)131 5527171, Website www.rbge.org.uk
Founded as a physic garden in 1670, the Royal Botanic Garden relocated to its third and present site at Inverleith, north of the city centre, in 1820. The site comprises 32 ha of undulating land with a sandy, acidic soil. It has 1.5 ha of glass, including an elegant Temperate Palm House, built in 1858, which is still the tallest in Britain. The Garden is funded by the Scottish Executive Environment and Rural Affairs Department, and through scientific research and education, explores and explains the world of plants. Specialist collections of conifers, Ericaceae (particularly Rhododendron), Gesneriaceae, Umbelliferae, Zingiberaceae. Catalogue available online.
Altitude 20–40 m. Zone 9. Rainfall 637 mm. January mean min. 0.7 °C, absolute min. –15.5 °C; July mean max. 19 °C, absolute max. 27 °C.
State-owned: Glasnevin, Dublin 9, Ireland
Glasnevin covers 19.5 ha of gently undulating terrain, including higher ground and the low-lying floodplain of the Tolka River. The soil is a shallow loam over gravel. Established by the (Royal) Dublin Society in 1795, aided by grants from the Irish Parliament, the gardens are Ireland’s premier botanical and horticultural institution. A public institution since 1878, they are now managed by the Office of Public Works. Since the early 1990s there has been major restoration and rejuvenation of the gardens, improving the Victorian glasshouses and constructing a new Library and National Herbarium building and Visitor Centre. A satellite arboretum at Kilmacurragh, Co. Wicklow is also managed by the National Botanic Gardens. Specialist collections of Acer, Arbutus, Cupressaceae, Ericaceae, Ilex, Pinaceae, Quercus, Rosaceae, Salix, Taxaceae. Catalogue available online.
Altitude c.20 m. Zone 9. Rainfall 724 mm. January mean min. 1.7 °C, absolute min. –19.6 °C (January 1982); July mean max. 19.3 °C, absolute max. 27.8 °C.
Mr Lawrence Banks:
Hergest Estate, Kington, Herefordshire HR5 3EG, UK
Hergest Croft comprises 30 ha of hilly land with neutral soil. The collection was started in 1895 by William Hartland Banks, though some specimens date back to the 1860s. W.H. Banks bought extensively from Veitch’s Nursery from 1900 onwards, but also from Vilmorin and Chenault’s Nurseries in France. He also received plants from Werrington and Caerhays (UK). Richard Banks, whose special interests were Acer and Betula, subsequently extended the collection, with many plants coming from Hillier Nurseries. Since 1985 the arboretum has been cared for by Lawrence and Elizabeth Banks, and it has new plant accessions from China and elsewhere, from many contemporary collectors. National Plant collections of Acer, Betula, Zelkova.
Altitude 195–260 m. Zone 8. Rainfall 1000 mm. Temperature records are not kept, but in general winters are mild and summers cool. Winter temperatures below –5 °C are unusual, and the summer maximum rarely exceeds 27 °C.
Hampshire County Council:
Jermyns Lane, Ampfield, Romsey, Hampshire SO51 0QA, UK
The Hillier Gardens (often called the Hillier Arboretum) were founded in 1953 by the late Sir Harold Hillier as a private arboretum surrounding his residence, Jermyn’s House. The Hillier family have been nurserymen around the nearby town of Winchester since 1864. The garden has been a charitable trust since 1977, with Hampshire County Council as sole trustee. The soil is mostly neutral on London clay, with an acidic area of Bagshot sand. The collection contains around 12,000 taxa, and is one of the most comprehensive anywhere, with both cultivars and wild-origin material. Twelve National Plant Collections, including Carpinus, Cornus, Corylus, Lithocarpus, Metasequoia, Pinus, Quercus (depository for the International Oak Society). A herbarium is maintained, with all specimens digitised. Catalogue available online.
Altitude 27–60 m. Zone 9. Rainfall 750 mm. January mean 3.8 °C, January mean min. 1.0 °C; July mean 16.5 °C, July mean max. 21.1 °C.
Lord (Charles) Howick:
Howick Hall, Alnwick, Northumberland NE66 3LB, UK
Howick, near the Northumberland coast, has one of the United Kingdom’s largest collections of wild-origin plants, growing over an area of approximately 26 ha. Opened to the public in 2006, it accommodates a large number of seed-grown trees, arranged according to their country of origin. The collection was begun in 1985 and now includes over 11,000 trees, with a strong emphasis on the native trees of China and Japan. Although one of the youngest arboreta in the United Kingdom, Howick presents a huge diversity of species, many of which are recent introductions of known wild origin. Collections have been made during overseas expeditions, often in conjunction with Quarryhill Botanical Garden or the Royal Botanic Gardens, Kew. No catalogue available, but accessions may be found via the Asian Plant Database (see www.quarryhillbg.org/asianplantdatabase.html).
Altitude c.40 m. Zone 8. Rainfall 651 mm. January mean min. 1.3 °C; July mean max. 17.9 °C.
North Carolina State University (NCSU):
4415 Beryl Road, Raleigh, North Carolina 27606, USA
Tel. +1 (0)919 515 3132,
The JC Raulston Arboretum comprises 10 ha of gently rolling terrain on the boundary between the Piedmont Plateau and the Coastal Plain. Soils are brown sandy loam underlain by red clay; pH 5.0–6.0. The arboretum was founded in 1976 by the late Dr J.C. Raulston, a renowned plantsman and professor of horticultural science at NCSU, to educate horticulture students and evaluate new plants for southern landscapes. Originally called the NCSU Arboretum, it was renamed the JC Raulston Arboretum in 1997. Today it is a nationally acclaimed garden, with one of the largest and most diverse collections of landscape plants in the southeastern United States. Specialist collections of Acer palmatum, Aesculus, Cercis, conifers, Ilex, Magnolia, Quercus (Mexican spp.), Styracaceae. Catalogue available online.
Altitude c.140 m. Zone 7b. Rainfall 1120 mm. January mean min. –1.2 °C; July mean max. 31.5 °C.
Royal Botanic Gardens, Kew:
Richmond, Surrey TW9 3AB, UK
The Royal Botanic Gardens, Kew evolved from two royal estates, a small botanic garden being founded in 1759. Part of the landscape, several buildings and some surviving trees date to this period. Greatly developed by Sir Joseph Banks between 1771–1820, and reinvigorated by Sir William Hooker and his son Sir Joseph in the nineteenth century, Kew became recognised as one of the great botanic gardens of the world. Its Herbarium, with over 7 million specimens, is one of the largest in the world, and also maintains an unrivalled collection of botanical art. Molecular research is carried out in the Jodrell Laboratory, and the Millennium Seed Bank is housed at Wakehurst Place. A strong emphasis is placed on the need for conserving the world’s flora. The garden covers 121 ha on a flat site, on generally sandy soil near the Thames, much of it comprising the Arboretum, filled with a great diversity of trees. Most recent plantings are of documented wild origin. The gardens, with their fine buildings and glasshouses, were designated a UNESCO World Heritage Site in 2002, and were further enhanced for tree-lovers in 2008 by the opening of the Rhizotron and Xstrata Treetop Walkway, giving a new view of treetops and tree roots. No catalogue, though some basic accession data available (www.rbgkew.org.uk/epic).
Altitude 6 m. Zone 9. Rainfall 627 mm. January mean min. 1.7 °C, absolute min. (1985–2004) –12.0 °C (January 2000); July mean max. 23.3 °C, absolute max. 38.1 °C (August 2003).
Ecole Nationale du Génie Rural des Eaux et des Forêts: L’Arboretum National des Barres,
45290 Nogent-sur-Vernisson, France
Tel. +33 (0)2 38 97 62 21,
The domaine of Les Barres was acquired in 1821 by Philippe André de Vilmorin, of the French nursery dynasty, remaining in the family until 1921 when it was donated to the French state. Many important collections made in China in the late-nineteenth and early-twentieth centuries by French collectors and others were planted, and form the core of the 35 ha botanical arboretum. The adjoining 300 ha are plantations where forestry research is carried out. Specialist collections of Abies, Acer, Crataegus, Picea, Pinus.
Altitude 150 m. Zone 8. The following meteorological data from Sully-sur-Loire (118 m) (Weatherbase 2008). Rainfall 640 mm. January mean 3 °C, absolute min. –15 °C; July mean 18 °C, July mean max. 22 °C, absolute max. 40 °C.
Royal Botanic Garden Edinburgh:
Port Logan, Stranraer, Dumfries & Galloway DG9 9ND, UK
Comprising 10 ha of gently undulating land at Scotland’s most southerly tip, underlain with a neutral to acidic loam soil, Logan is unrivalled as the country’s most exotic garden. A colourful walled garden of tree ferns, palms and borders contrasts with a woodland area with Gunnera bog and collections of southern-hemisphere trees and shrubs. Since 1969, when it became a regional garden of the Royal Botanic Garden, many new wild-collected trees and shrubs have been planted, particularly from New Zealand, Chile and Tasmania. Specialist collections of Azara, Eucalyptus, Eucryphia, Rhododendron, Weinmannia. Catalogue available online.
Altitude 25–40 m. Zone 9. Rainfall 1000 mm. January mean 6 °C, January mean min. 3 °C, absolute min. –10.5 °C (December 1995); July mean 16.9 °C, July mean max. 21.1 °C, absolute max. 27.7 °C (July 2006).
University of Pennsylvania: 100 E. Northwestern Avenue, Philadelphia, Pennsylvania 19118, USA
The 64 ha Morris Arboretum includes 37 ha of public gardens with a varied terrain, ranging from floodplain to ridge top. Soils are well drained and largely acidic, but for an alkaline pocket above limestone. Founded in 1887 as the private estate of John and Lydia T. Morris, the Morris Arboretum of the University of Pennsylvania was established in 1932 as a university-administered arboretum and public garden for research, education and horticultural display. It became the official Arboretum of the Commonwealth of Pennsylvania in 1988. Specialist collections of Acer, conifers, Hamamelis, Ilex, Magnolia, Rosa. A printed catalogue is available.
Altitude 76 m at highest point. Zone 6b. Rainfall 1090 mm. January mean 0.5 °C, January mean min. –5 °C; July mean 25.6 °C, July mean max. 30 °C.
Private, Not for Profit organisation:
4100 Illinois Route 53, Lisle, Illinois 60532-12, USA
The Morton Arboretum covers 690 ha of level terrain, including glacial uplands and the floodplain of the DuPage River. The underlying soils are silty-loam to clay. Established in 1922 by Joy Morton (1855–1934), owner of the Morton Salt Company, the arboretum has extensive plant collections, gardens, lakes, natural woodlands and restored prairie, and an award-winning children’s garden. A complete revitalisation of the central visitor area was completed in 2005. The arboretum features notable collections of Chinese, Appalachian, Ozarkian and Midwestern plants of wild-collected origin. Specialist collections of Acer, Malus (crabapples), Quercus, Ulmus. Catalogue available online, and printed.
Altitude 201–245 m. Zone 5a. Rainfall 920 mm. January mean –5.6 °C, January mean min. –9.8 °C, absolute min. –32 °C (January 1982); July mean 16.9 °C, July mean max. 22.9 °C, absolute max. 40.5 °C (July 1934).
Mrs Madelaine Jay:
Ashford, Co. Wicklow, Ireland
Mount Usher Gardens are laid out over 9 ha of land in the valley of the River Vartry in Co. Wicklow, on a rich alluvial soil. Created from 1868 by the Walpole family, Mount Usher is Ireland’s finest Robinsonian garden. The planting includes over 5000 species from all over the world, including many rare, tender exotics and a number of Irish champion trees, such as a renowned Pinus montezumae which dates from c.1900. Specialist collections of Eucryphia, Nothofagus. Catalogue available at reception.
Altitude 25 m. Zone 8. Rainfall 900 mm. Jan. mean 9 °C, Jan. mean min. –3 °C, absolute min. –6 °C (March 2004); July mean 21 °C, July mean max. 26 °C, absolute max. 29 °C (July 2006).
Private, Not for Profit organisation:
12841 Sonoma Highway, Glen Ellen, California 95442, USA
Quarryhill comprises 9 ha of garden on a west-facing slope of the Mayacamas Mountains. The soils are acidic, derived from volcanic rock. Founded in 1987 by Jane Davenport Jansen (1940–2000), the collection consists largely of wild-origin plants (over 90%) grown from seed collected on annual expeditions to Asia – primarily China, but also Japan, Taiwan, India and Nepal. Accessions may be found via the Asian Plant Database (www.quarryhillbg.org/asianplantdatabase.html), which also lists holdings of Asian plants in many other collections.
Altitude 60–90 m. Zone 9. Rainfall 900–1000 mm. January mean min. 2 °C, absolute min. –10 °C (December 1990); July mean max. 27 °C, absolute max. 42 °C (July 2006).
Guy and Edie Sternberg:
12000 Boy Scout Trail, Petersburg, Illinois 62675, USA
Starhill Forest extends over approximately 20 ha of gently rolling land with silt-loam to clay-loam soils (pH 6.5). Founded in 1976 by Guy and Edie Sternberg, Starhill holds one of the most comprehensive collections of oak (Quercus) in North America. Specialist collections of Quercus and other Fagaceae; also of Acer, Anacardiaceae, Betulaceae, Juglandaceae, Pinaceae, Ulmaceae. Catalogue unavailable, but online photograph albums may be viewed.
Altitude c.180 m. Zone 5. The following meteorological data from Springfield, Illinois (181 m) (Weatherbase 2008). Rainfall 800 mm. January mean –2 °C, January mean min. –7 °C, absolute min. –23 °C; July mean 25 °C, July mean max. 31 °C, absolute max. 38 °C.
Mr T.C. Hudson:
Tregrehan House, Par, Cornwall PL24 2SJ, UK
Over 15 ha of sloping land on acidic, free-draining loam, Tregrehan displays a botanical collection built up by the Carlyon family over the past 160 years. The plants are mainly from warm temperate areas, and the garden’s fertile soil, sheltered aspect and favourable climate have allowed many exotic species to reach record sizes. Many of the recent accessions are wild-collected and of known source, and the emphasis is on conservation of rarer species. Direction is presently provided by a small steering committee led by representatives from the Royal Botanic Gardens, Kew, who monitor the nature and extent of current planting, within the surrounding historical landscape. Specialist collections of Aceraceae, Araliaceae, Ericaceae, Flacourtiaceae, Hamamelidaceae, Lauraceae, Magnoliaceae, Pinaceae, Podocarpaceae, Styracaceae, Theaceae. A printed catalogue is available.
Altitude 50 m. Zone 9. Some meteorological data from Falmouth, Cornwall (60 m) (Weatherbase 2008). Rainfall 1150– 1200 mm (Tregrehan data). January mean 6 °C, January mean min. 4 °C; July mean 15 °C, July mean max. 19 °C.
Stichting Arboretum Trompenburg:
Honingerdijk 86, 3062 NX, Rotterdam, The Netherlands
Trompenburg Arboretum occupies 8 ha of flat, formerly cultivated polderland along the River Maas, with shallow, humus-rich clay soil and a high water-table. Formerly the private property of the van Hoey Smith family, Trompenburg dates back (in part) to 1820, when pastures were transformed into a naturalistic parkland. Since then its are has been extended, in 1870, 1970, 1996 and 2001. The collection of trees and shrubs began in the 1920s. Trompenburg has been managed by the Stichting Arboretum Trompenburg since 1985. Specialist collections of dwarf conifers, Fagus, Ilex, Quercus, Rhododendron. Catalogue: see Trompenburg Arboretum, Green Oasis in Rotterdam, by J.R.P. van Hoey Smith (2001).
Altitude 1.2 m below sea-level. Zone 7–8. Rainfall 850 mm. Jan. mean 3 °C, Jan. mean min. 1 °C, absolute min. –18 °C (1963); July mean 17 °C, July mean max. 21 °C, absolute max. 31 °C.
United States Department of Agriculture (USDA):
3501 New York Avenue, N.E., Washington DC 20002, USA
Tel. +1 (0)202 245 2726, Website www.usna.usda.gov
Situated largely on the floodplain of the Anacostia River, the 180 ha US National Arboretum has a diverse terrain and soil profile. The arboretum was founded by an Act of Congress on 4 March 1927, for the ‘purposes of research and education concerning tree and plant life’. The primary focus has been to support ornamental plant-breeding work in the USDA, serving as a repository for research plants and germplasm collected by USDA scientists. The grounds were officially opened to the public in 1948, and the collections are now visited by 450,000 people a year. Specialist collections of Acer, Buxus, azaleas, dwarf conifers, Ilex, Magnolia. The accessions database is not available to the general public, but individual accessions can be identified at the plant locator kiosk.
Altitude 3–73 m. Zone 7a. Rainfall 1100 mm. January mean 1.3 °C, January mean min. –3.8 °C, absolute min. –23.3 °C (January 1982); July mean 25.5 °C, July mean max. 31.4 °C, absolute max. 40 °C (July 1954, August 1997).
University of British Columbia: 6804 Southwest Marine Drive, Vancouver, British Columbia V6T 1Z4, Canada
The garden (about 44 ha) is located on the western edge of the city of Vancouver, to the southwestern side of Point Grey Peninsula, atop cliffs that descend to the Strait of Georgia. The original botanical garden began in 1912 at Colony Farm, Essondale, just east of Vancouver. John Davidson was appointed provincial botanist, and built up a collection of over 9000 species. In 1916 the collection was moved to the Point Grey campus and Davidson became the first director of the UBC Botanical Garden. This is now an academic unit within the Faculty of Land and Food Systems. Specialist collections of Acer, Cornus, Eucalyptus, Lauraceae, Magnoliaceae, Rhododendron, Sorbus, Styracaceae. Catalogue available online.
Altitude 76 m. Zone 8b. Rainfall 1226 mm. January mean min. 1.2 °C; July mean max. 20.4 °C.
University of Utrecht:
Velperengh 13, 3941 BZ, Doorn, The Netherlands
Tel. +31 (0)30 2531826, Website www.bio.uu.nl/botgard/
This arboretum extends over 27 ha of low-lying, flat ground with a sandy soil. Founded in 1924 by Max von Gimborn, who specialised in conifers, it was adopted after his death in 1964 by the University of Utrecht, when new collections were added. In the late 1980s the whole collection was databased, and in 2001–2003 coordinates were added for every accession, allowing accurate mapping. Highlights include the Heather garden and the Rhododendron and Tsuga forests. Specialist collections of Acer, Betula, conifers (esp. Tsuga), Ericaceae (esp. Rhododendron), Euonymus, Fraxinus, Laburnum, Magnolia, Syringa. Catalogue available online.
Altitude 3 m. Zone 7. Rainfall 803 mm. January mean 2.8 °C, January mean min. –0.6 °C, absolute min. –24.8 °C; July mean 17.4 °C, July mean max. 21.6 °C, absolute max. 36.8 °C.
Royal Botanic Gardens, Kew: Selsfield Road, Ardingly, Haywards Heath, West Sussex RH17 6TN, UK
Situated on the Sussex High Weald, Wakehurst Place comprises approximately 210 ha of woodland, meadows, wetlands and landscaped gardens along a steep-sided valley, running down to a reservoir. The site has been managed by Kew on behalf of the British government since 1965, when the estate was bequeathed to the National Trust by Sir Henry Price. The climate and topography at Wakehurst, and its existing collections – originally made by Gerald Loder and Sir Henry Price – greatly increased Kew’s scope to expand and develop collections that did not grow well in London. The temperate tree and shrub collections are planted out in a phytogeographical arrangement, and there are important collections of southern-hemisphere plants. Specialist collections of Betula, conifers, Nothofagus, Rhododendron. No catalogue, though some basic accession data are available (www.rbgkew.org.uk/epic).
Altitude 133 m at highest point. Zone 6–7. Some meteorological data from Horsham, West Sussex (51 m) (Weatherbase 2008). Rainfall c. 820 mm (Wakehurst data). January mean 4 °C, January mean min. 2 °C, normal annual min. –5 to –8 °C (Wakehurst data); July mean 16 °C, July mean max. 22 °C, absolute max. 37.6 °C (Wakehurst data).
Warsaw Agricultural University: PL-95-063 Rogów, Poland
The Rogów Arboretum consists of 54 ha of woodland on acidic, often podzolic soils. It was established in 1925 as a research and training site for scientists and students of the Forestry Faculty of Warsaw Agricultural University. The main objective was to assess the usefulness for Polish forest economy of different foreign tree species. To achieve this goal, numerous forestry trial plots were established, with a small number of specimen trees and shrubs planted in between. The collection became significant only after World War II, when permanent staff were employed for the first time and a nursery and greenhouse were constructed. Specialist collections of Acer, Araliaceae, conifers, Sorbus, Stewartia. Catalogue available online.
Altitude 185–196 m. Zone 6b. Rainfall 600 mm. January mean –3.2 °C, January mean min. –6.1 °C, absolute min. –34 °C (February 1929); July mean 17.3 °C, July mean max. 22.9 °C, absolute max. 36.2 °C (August 1992).
University of Washington Botanic Gardens:
2300 Arboretum Drive East, Seattle, Washington 98112, USA
Washington Park occupies a site of 93 ha in a shallow valley with a north-south trending axis; the soils are extremely variable. The arboretum was established in 1934 through an agreement between the University of Washington and the City of Seattle. A large tract of city-owned park land known as Washington Park was selected and made available. Under the agreement, the City of Seattle manages all park functions and the University is charged with the design, creation and management of the arboretum and botanic garden plant collection. The Arboretum Foundation was established in 1935 and has been an active support group since that time. Specialist collections include Abies, Acer, Betula, Ilex, Magnolia, Nothofagus, Pinus, Quercus, Sorbus. Printed catalogue available. For more information online, see Arboretum website (depts.washington.edu/wpa/collection.htm).
Altitude 6–50 m. Zone 8. Rainfall 945 mm. January mean 4.5 °C, January mean min. 1.8 °C, absolute min. –18 °C (January 1950); July mean 18.5 °C, July mean max. 24 °C, absolute max. 37.8 °C (July 1994).
Foundation Arboretum Wespelaar:
Grote Baan 63, 3150 Haacht-Wespelaar, Belgium
Arboretum Wespelaar extends over 15 ha of largely flat land with heavy, poorly drained, loam soil; acid soils predominate, though there are some neutral pockets (pH 3.4–7.6). The Arboretum Foundation was established in 2001 to manage the botanical collections of Philippe de Spoelberch and the adjacent private garden, Herkenrode (10 ha). The tree collections at Wespelaar and Herkenrode were begun in 1985 and 1965, respectively. The arboretum contains around 2800 specimens of trees and shrubs, including many rare species collected in their natural habitat, as well as numerous cultivars and selections. Specialist collections of Acer, Betula, Carpinus, Fagus, Fraxinus, Ilex, Lindera, Liquidambar, Magnolia, Quercus, Styrax, Tilia. Catalogue available online.
Altitude 8–14 m. Zone 6–7b. Rainfall 900 mm. January mean 2.3 °C, January mean min. –4.4 °C, absolute min. –19 °C (January 1985); July mean 19.3 °C, July mean max. 30.8 °C, absolute max. 44 °C (August 2003).
The Forestry Commission:
Westonbirt, Tetbury, Gloucestershire GL8 8QS, UK
Westonbirt is planted over 250 ha of largely flat ground, with soils varying from acid loam to base-rich clay-loam. Since 1956 the arboretum has been owned and managed by the Forestry Commission. The basic layout was established in one phase between 1854 and 1881, under the guidance of its creator Robert Staynor Holford and his son Sir George Holford. Apart from some single genus collections in Silk Wood, most subsequent development has been carried out within this original framework. In addition to its botanical value, the arboretum, owing much to the influence of nineteenth-century landscape design, has many identifiably ‘Picturesque’ elements – possibly resulting from Robert Holford’s known appreciation of the work of W.S. Gilpin. National Plant Collection of Acer. Catalogue available online (www.thewestonbirtmap.org.uk). The National Arboreta managed by the Forestry Commission also include Bedgebury, the National Pinetum in Kent (see above), home of the most complete collection of conifers in the world.
Altitude 130 m. Zone 7. Rainfall 850 mm. January mean 4.1 °C, January mean min. 1.3 °C, absolute min. –12.9 °C (January 1999); July mean 16.4 °C, July mean max. 21.3 °C, absolute max. 32.6 °C (August 1995).