Rhododendrons are one of the most important groups of plants in the gardens of the British Isles and of North America, yet most species come from Asia and from the tropical vireyas from the mountains of New Guinea. Their popularity since their early introduction has led to a long history of adventure, exploration, intrigue, horticultural expertise and scientific experiment. All of that and a lot more is recounted in this fascinating and extensively researched volume, which takes one all over the world, through 300 years of gardening history and into many botanical details.

There are 1,025 known wild species of rhododendrons, and they are a promiscuous lot because many can hybridise even with species from a different continent. The result is myriad possible combinations that have led to the many varieties now available. This has also led to much competition between the different rhodo fanciers to outdo their rivals. To write about rhododendrons is to recount the history of horticultural exploration, of the famous gardens, of gardeners and botanists of Britain and elsewhere, of landscape gardening and of the commercial nurseries of the past and present. All these aspects and much more are carefully interwoven here.

Ever since the first rhododendrons (which includes what we call azaleas) reached England, they have fascinated gardeners, estate owners and even royalty. John Bartram (1699-1777) seems to have started the craze with the many boxes of living American plants he sent to his London merchant Peter Collinson over a 35-year period. It was from some of these that Linnaeus, the founder of plant and animal nomenclature, coined the name "rhododendron" from "red rose", hence the title of the book.

In 1814, the Edinburgh Botanic Garden recorded the first hybrid rhododendron in Britain when R. periclymenoides , the North American Pinxterbloom, was crossed with the now common R. ponticum to produce a hybrid named "odoratum". Soon a rash of hybrids began, and much of their history is given throughout the book. As each collector brought in new species, the potential for new hybrid varieties increased, and the nurserymen and estate owners both made good use of them. The travels of all the well-known collectors of rhodos are discussed, such as Robert Fortune (1812-80) in China, after whom the "cloud brocade rhododendron", R. fortunei , with its nodding, scented, lilac-blushing pink flowers was named. Also in China was Augustine Henry (1857-1930), who is commemorated by R. augustini . These were soon followed by Joseph Hooker (1817-1911) in the Himalayan region, Ernest Wilson (1876-1930) and George Forest (1873-1932), the last collecting for the Royal Botanic Garden Edinburgh. The hunt for new rhodos has been continued to the present day by such people as George Argent, also from Edinburgh, who brought back many of the tropical vireya rhododendrons.

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As the collections of all these people, and many others, were much sought after by the owners of stately homes and by nurserymen, this book is also a tour of many famous homes. The Williams dynasty in Cornwall at Burncoose, Caerhays and other Cornish gardens, who received many of Forest's collections, feature frequently. Lionel de Rothschild and his successors made Exbury into one of the most famous of all rhododendron gardens.

We read of the Lords Aberconway collecting rhodos for Bodnant, and of Harry Mangle's collection at Littleworth, the garden that the author claims was the prime inspiration for this book. Littleworth's history of ups and downs is typical of many of the mansions discussed. The garden was created by Mangle and his sister in the 1880s. After being owned by several rhodo fanciers, the site became a boys' school in the Second World War before being rescued by Violet Gordon and her son Adam.

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Another claim to fame was that it was at Littleworth that neighbour Gertrude Jekyll (1843-1932) first met the young architect Edwin Lutyens, which led to an inspiring partnership that was to benefit many houses and gardens. Princess Augusta, with the help of the Earl of Bute, collected rhodos at Kew. Frederick, Prince of Wales, Queen Charlotte, Edward VII and other royals, gathered rhodos at Frogmore, Virginia Water, Sandringham and Saville Gardens, and so the long history of royal horticulture is told here.

Not all is good news about rhodos. R. ponticum is well known as an invasive species in many places. Its good and bad points are the subject of one chapter. This plant is considered a weed and an enemy by many ecologists, but it is also one of the parents of many of the early and popular hybrids and so it is well defended here.

This is much more than a book on rhododendrons. It is an engaging history of British horticulture, exploration, history and stately homes and their owners all told through the story of the genus Rhododendron .

Sir Ghillean Prance is scientific director, Eden Project, and was formerly director, Royal Botanic Gardens, Kew.

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