The classic British* reference book on trees, shrubs and climbers is The Hillier Manual of Trees and Shrubs. My copy sits with a small and very select group of references just to left of my computer monitor; I probably use it every day.
Now, a new revised edition of this classic has been released by the Royal Horticultural Society, twelve years after the last edition. It has been significantly updated and expanded to include an amazing total of 13,215 individual plants (plus 3,258 cross-references and synonyms) from 706 genera; 1,490 plants have been added to those in the previous edition and this confirms the book’s status as the essential reference on woody plants for British gardeners.
As you can tell, it’s comprehensive. I’ve only failed to find one shrub I’ve looked up over the last few months and believe me I check on some pretty unusual plants. Another thing is that, as with my Encyclopedia of Perennials, the descriptions are written in accessible language – you don’t need to be a professional botanist to understand what’s being said. So no words like “bipinnatifid” and “orbicular” except where absolutely necessary (and of course there’s an easy glossary).
Wherever possible the text notes when species were introduced to western gardens, who discovered them in the wild and who introduced or developed cultivars and other interesting snippets of information. I’m pleased to see that plants which have been awarded the Royal Horticultural Society’s prestigious Award of Garden Merit (AGM) are marked but plants are not given hardiness ratings – not the USDA ratings nor the new RHS ratings. I’m told that the RHS hardiness ratings will added in a future edition.
This medium format book has no colour pictures, and so is priced at under £20 for almost 600 pages of the highest quality information. And it’s worth mentioning that commenters on amazon.co.uk are comparing the book unfavourably with previous editions because there are no colour pictures. But as far as I’m aware the Hillier Manual never had colour pictures; they’re confusing it with the old, extremely outdated and much less useful Hillier Colour Dictionary of Trees and Shrubs and Hillier Gardener's Guide to Trees and Shrubs which included many colour pictures – but covered far far fewer plants.
And, as Roy Lancaster says in his preface: “Even without illustrations, it offers a window on the wonderful world of woody plants to be seen, admired, cherished and ultimately enjoyed.”
But one thing that disappoints me. Bamboos are included, over thirty pages of Rhododendron hybrids are included, there are seven pages of Clematis hybrids – but only ten pages of roses, and none of the huge number of hybrid roses that are so widely available. Considering that in much of the country it’s impossible even to grow rhododendrons (because they need acid soil), to include so many seems perverse when at the same time excluding roses – which anyone anywhere can grow.
The RHS tell me that this is a matter if history - Hillier Nurseries, who developed the original manual in 1971, were never big on roses - and also that modern rose introductions disappear so quickly it would be impossible to keep the book current. My view is that while roses may not have been important to Hillier Nurseries, they're very important to gardeners and including old roses, or AGM roses, at the very least, would have been very helpful.
Finally, let me mention the book’s stout binding (although it’s a paperback it should last like a hardback), its clear typography and layout, and its valuable updated lists of plants for purposes. Excellent.
In all, this is an essential reference, with far more information for your money than any other guide to trees and shrubs.
* I should make clear that, while the book is intended for British gardeners, serious enthusiasts for shrubs in North America and around the world will find plants and information included that are in no other reasonably priced guides – or, in many cases, in any other guides at all.
The Hillier Manual of Trees and Shrubs is published by the Royal Horticultural Society.