The Complete Guide To: Botanical Britain

What is a botanic garden exactly?

Definitions have changed over time, and they can sound off-putting. A contemporary one, "institutions holding documented collections of living plants for the purposes of scientific research, conservation, display and education", doesn't begin to convey the pleasure they can offer to non-botanists. It's the remarkable characteristic of botanic gardens that they can be enjoyed in many different ways – by the most knowledgeable of plant taxonomists as well as by people who can't tell an azalea from a rhododendron. Little regard was originally given to the aesthetic arrangement of plants, but many botanic gardens now devote as much effort to presentation as country-house gardens.

For gardeners, botanic gardens are like a living catalogue; future generations will be thankful for their work in creating seed banks. Most botanic gardens are in or near urban areas and provide spectacular green lungs and space for residents and visitors; many now also gently educate in the importance of the natural world.

The first botanic gardens were narrowly functional: known as physic gardens, they were intended to provide plants that could be used in medicine. The first was founded in Pisa in 1543, and they can be seen as a development of the monastic garden, in which all manner of plants were grown, whether or not their use was known (it was thought that all plants must be of use to man).

Which was the first in the British Isles?

The oldest is Oxford Botanic Garden (01865 286690; www.botanic-garden.ox.ac.uk), founded in 1621 by Henry Danvers, first Earl of Danby, whose portrait by Van Dyke hangs in the Hermitage in St Petersburg. He leased from Magdalen College 4.5 acres of riverside land and gave £5,000 (about £3m-4m today) "for the glorification of God and for the furtherance of learning". The land was soon ringed by the high stone walls that stand today, enclosing the traditional borders and glasshouses for lilies, orchids and palms; outside the walls are the Water Garden and Rock Garden. The garden contains over 8,000 different plant species, some laid out in beds to illustrate their uses, such as thorn apple, which is being tested for the treatment of Parkinson's disease. The garden has provided inspiration for various writers, from Lewis Carroll to Tolkien – who would sit under his favourite tree, the enormous Ent-like black pine (Pinus nigra) from Austria – to Philip Pullman, who used the wooden bench at the back of the garden in The Amber Spyglass. The garden is open daily from 9am to 4.30/5/6pm depending on the month; admission is £3, or £10 for an annual pass.

Are there any traditional physic gardens left?

The best known is Chelsea Physic Garden (020-7352 5646; www.chelseaphysicgarden.co.uk), established in 1673 as the Apothecaries' garden. Thanks to Dr Hans Sloane (after whom nearby Sloane Square is named), the 3.5 acre garden is held on a lease of £5 a year in perpetuity. Its early seed-exchange programme helped introduce cotton into the American state of Georgia. It's tucked away behind tall brick walls on Royal Hospital Road and has been open to visitors only since 1983. It's secluded and intimate, and the heat-trapping walls help to grow some trees rare in Britain, such as the most northerly outdoor grapefruit and the largest fruiting olive. The garden (and usually café) is open noon-5pm Wednesday to Friday and noon-6pm Sunday, until 10pm on Wednesdays in July and August; admission is £7.

The Edinburgh Royal Botanic Garden (0131 552 7171; www.rbge.org.uk) was established on its present 69-acre site in the 1820s. Yet it dates from a garden set up in 1670 to teach the medicinal use of plants to medical students. It's now renowned for the largest collection of wild-origin Chinese plants outside China, for its vast rock garden of moraines and streams with over 5,000 alpine plants, and for the Scottish Heath Garden, which re-creates the landscape of the Highlands. It's open daily from 10am-5/6/7pm depending on the month; admission is free (except for the glasshouses).

Why is there often a queue for Kew?

With more than 1.3 million visitors a year, the Royal Botanic Gardens (020-8332 5000; www.kew.org) can be busy on sunny days at key times of the year for colour, but there are four entrances, and frequent visitors may find it worth becoming a Friend (£33–£65), which allows unlimited admission (and no queueing). Covering over 300 acres beside the Thames at Kew in south-west London, it is the largest and most important botanic garden in the UK. Along with the jointly managed Wakehurst Place in West Sussex, it has probably the largest and most diverse living collection in the world.

Kew has been developed from two adjacent royal gardens landscaped by some of Britain's finest landscape designers, such as Capability Brown and Sir William Chambers, who in 1761, as a surprise for Princess Augusta, designed the 10-storey Great Pagoda that dominates the south-east corner; he also designed the Orangery and three temples.

Two years earlier, a nine-acre botanic garden was founded, marking the beginning of the garden's scientific purpose, though its earlier history has helped Kew retain its artistically pleasing design and plantings. It is impossible to see everything in one visit, with miles of paths and over 40 listed buildings, as well as exhibitions and displays. To find tranquillity even on a busy day, head for the south-western corner around the cottage ornée (created for Queen Charlotte, George III's wife), in the oldest area of continuous woodland in the garden. The cottage was used for the occasional meal, and the natural state of the bluebell woods is thanks to a stipulation by Queen Victoria; though her request was not entirely honoured after her death, it remains the wildest part of the garden.

In May, a new Rhizotron walkway underground and contrasting Xstrata treetop walkway will open, the latter taking visitors high into the tree canopy.

The gardens open daily from 9.30am to 5.30/6/6.30 /7.30pm depending on the day and month; admission is £13.

Anything there for the 21st-century botanic traveller?

Besides the plants themselves, a new gallery devoted to botanical drawing and painting – the world's first – has opened. The Shirley Sherwood Gallery of Botanical Art kicks off with an exhibition showing the scope and richness of Kew's and Dr Sherwood's collections, with many of the pictures on public display for the first time.

Kew has one of the world's greatest collections of botanical art, over 200,000 items by masters such as GD Ehret, the Bauer brothers and Redouté alongside 19th-century artists such as Walter Hood Fitch, one of the most prolific botanical artists.

Besides its size and scope, the importance of Kew's collection lies in having the only surviving record of some extinct species. Dr Sherwood's complementary collection of contemporary botanical art by over 200 artists from 30 countries is also on long loan to Kew. The striking new glass building is linked with the nearby Marianne North Gallery, a permanent display of 832 botanical and landscape paintings by that redoubtable Victorian traveller and artist, who was as keen to show the context of a plant as the plant itself.

Many of the pictures are astonishingly beautiful, and the remarkable detail and subtlety make it easy to appreciate why photography has not killed botanical art, even for scientific research. The opening exhibition runs until 19 October, to be followed by an exhibition of tree subjects from 1 November.

Anything else?

Botanic gardens can also transport visitors by re-creating different climates. It was in this arena that Victorian ingenuity really came to the fore. New materials made available by the industrial revolution allowed the u o construction of huge buildings with an uninterrupted floor area. Shipbuilding technology was used to create buildings that look like upturned hulls.

The precursor of the palm houses that became so popular in botanic gardens was Sir Joseph Paxton's Great Stove at Chatsworth, erected in 1836–40. It was destroyed in 1920, so the oldest surviving palm house is in the Botanic Gardens in Belfast (028 9032 0202; www.belfastcity.gov.uk), begun in 1839.

Probably the finest example in the world, however, is the Grade I-listed wrought-iron and cast-iron palm house at Kew, built in 1844–8 to a design by Decimus Burton and Richard Turner. It was originally heated by coal-fired boilers, whose smoke was fed through underground pipes to the Italianate campanile chimney that still stands by the Victoria Gate Centre. The temperate house, twice as large as the palm house, is the largest Victorian glasshouse in existence.

The purpose of these buildings was to create a climate in which exotic flora could flourish, giving a sense of what tropical rainforest looked, smelled, and even (if birds were introduced) sounded like. They also illustrate the economic use of plants by showing the various products made from them.

Any other great iron glasshouses?

The first glasshouse at the Royal Botanic Garden, Edinburgh, predates Kew, and remains the tallest, at almost 72ft; the tropical palm house was built in 1834 and extended in 1862 by adding a temperate palm house. Visitors here can experience 10 distinct climatic zones.

Also combining various climatic habitats within a single building is the 1930s Glasshouse Range at Cambridge University Botanic Garden (01223 336 265; www.botanic.cam.ac.uk). Partly made of teak, the range has a replanting programme that explores how plants have evolved to survive in different environments, from icy mountains to desert and jungle. Covering 40 acres, the garden is an oasis of tranquillity, popular for lunchtime sandwiches away from the office. It was begun in 1831 by Professor John Henslow, the teacher of Charles Darwin, and opened in 1846. Henslow regarded trees as the most important plants, and they form the framework of the garden, though there are over 10,000 plant species, notably (and ironically for the Fens) alpine plants and lavenders. Open daily 10am-6pm; £4.

Specific species

Some botanic gardens focus on local plants, or on a particular species – sometimes holding the National Collection of a particular plant, which means that it's the most comprehensive in the UK. Cambridge University Botanic Garden (01223 336 265; www.botanic.cam.ac.uk) does both. It works to conserve and propagate rare plants of the fens and sandy Brecklands, as well as holding nine National Collections. Oxford Botanic Garden has the National Collection of euphorbias, while Bedgebury National Pinetum, in Kent (01580 879 820; www.bedgeburypinetum.org.uk), has the world's most comprehensive collection of conifers: 608 species. It's open daily 8am-4/5/6/7pm depending on the month; admission is £7.50/car.

For inspiration?

One of Britain's most visited gardens is Wisley, in Surrey (0845 260 9000; www.rhs.org.uk), which has been looked after by the Royal Horticultural Society since 1903. The 240 acres incorporate numerous formal and informal decorative gardens, several glasshouses, an extensive arboretum, small-scale "model gardens" and a trials field where new cultivars are assessed. Open 10am-6pm Monday to Friday, 9am-6pm at weekends from March to October; 10am-4.30pm Monday to Friday, 9am-4.30pm at weekends November to February; admission is £8.

Any birdwatching?

Visit the 85-acre Thorp Perrow Arboretum in North Yorkshire (01677 425 323; www.thorpperrow.com). The Bird of Prey & Mammal Centre offers participative flying demonstrations of eagles, falcons, hawks, vultures and owls. It's open daily 10am-5pm until mid-November, with flying displays at 11.30am, 1.30pm and 3.30pm; 11am-3pm until mid-February; admission is £6.60.

And when I've seen enough plants?

There are plenty of diversions in York Museum Gardens (01904 687 687; www.yorkshiremuseum.org.uk), with 4,500 plants and trees in the centre of York. Covering 10 acres of the former grounds of St Mary's Abbey, it is home to the remains of the Roman fort of Eboracum and the Yorkshire Museum, with its octagonal observatory. The gardens are open daily 7.30am-5.30pm; admission free.

Inside the gardens at Kew is Kew Palace (0844 482 7777; www.hrp.org.uk), the former home of George III and Queen Charlotte, which has re-opened after various improvements. It's open until 28 September 11am-5pm on Monday, 10am-5pm Tuesday to Sunday; admission is £5.

At Exbury Gardens in Hampshire (023 8024 5750; www.exbury.co.uk), a narrow-gauge steam railway takes you around the woodland garden, known for its rhododendrons, azaleas and camellias. The gardens are open daily from 10am-5.30pm until 9 November; admission is £7.50.

Some gardens host concerts. At Westonbirt (01842 814 612; www.forestry.gov.uk/westonbirt) you can hear Status Quo on 22 June and Jools Holland and his R&B Orchestra on 18 July; tickets are £30. Summer Swing at Kew (0871 231 0834) features The Commitments on 9 July, Lulu on 10 July and Gipsy Kings on 11 July; tickets from £30. Cornish choirs regularly perform in the biomes at the Eden Centre (01726 811 972; www.edenproject.com); this year's "Eden Sessions" features The Verve on 27 June, Kaiser Chiefs on 15 July and KT Tunstall on 25 July. Tickets £28-35.

Any new botanic gardens?

The most ambitious recent creation is the Eden Project (01726 811 911; www.edenproject.com). The three domes in the china-clay pits mimic three environments: the tropics, a warm temperate zone and the Mediterranean. The first is the largest greenhouse in the world, 3.9 acres of banana trees, coffee and rubber plants. Olives and grape vines fill the temperate biome. Its huge education centre, the Core, aims to communicate the project's central message, about the symbiotic relationship between people and plants. It's open daily 10am-6pm (last entry 4.30pm); admission is £15.

Where can I find out more?

The Botanic Gardens Conservation International (020- 8332 5953; www.bgci.org) links 2,500 institutions in 120 countries, working together to preserve and promote plant diversity.

AND IF YOU PREFER TREES TO FLOWERS...

Some arboretums are part of botanic gardens, others merely the result of a private passion for trees. One of the first surrounded the Bishop of London's Palace at Fulham, with North American specimens sent back (starting in 1675) from the relatively new colony in Virginia; some of them still survive in what is now a municipal park.

The National Arboretum at Westonbirt in Gloucestershire (01666 880220; www.forestry.gov.uk/westonbirt) is renowned for its autumn colours, thanks to what is expected to become the world's finest collection of maples. Covering 600 acres, it has over 3,000 species, with a major collection of oak. Open until the end of November from 9am-8pm Monday to Friday and 8am-8pm at weekends; admission is £7.

In complete contrast to the Oxford Botanic Garden is its arboretum at Harcourt, to the south of the city (01865 286690; www.botanic-garden.ox.ac.uk). The best time of year is May and June, when the azaleas and rhododendrons are ablaze, or October, when the Japanese maples are at their best. In summer there is also the all too rare sight of a wildflower meadow.