Not so long ago I talked to the commissioning editor at one of the top garden book publishers who said they weren’t commissioning any more books about plants because people could get all the information on plants they needed online. Well, not so fast. This gold standard of plant books proves them wrong.

Kniphofias are – as we say these days – trending, so the appearance of Kniphofia: The Complete Guide by Christopher Whitehouse is very timely. In the last six years one American breeder alone has introduced thirteen new varieties (including 'Orange Vanilla Popsicle', above) and the trial at the Royal Horticultural Society’s garden at Wisley that ended in 2009 revealed some fine older cultivars.

This book does everything a monograph should: in its 456 pages it classifies and describes the seventy species thoroughly and with insight; over a thousand cultivars are covered, 160 that are grown today are described in detail and illustrated - grouped by the color of their flowers so we can more easily distinguish one from another. We gain a valuable understanding of how and where kniphofias grow in the wild, courtesy of a botanist who’s studied them in their native habitats. And if you want to know how to grow them… well, look no further.

That’s all well and good, but if this wealth of information is not provided in an attractive and accessible way then why bother? Fortunately, the design is elegant and stylish yet straightforward and accessible; the color reproduction is excellent and whatever I need to know about kniphofias, this is where I turn.

And, in some ways, that’s the most important feature of all. There’s no room in the gardening book market for more than one book on kniphofias, so the one that appears has to cover, well, everything. In recent years a number of plant books have appeared that have not been comprehensive but which have, by their very existence, prevented another book taking up the slack.

This is the first in a series of plant monographs from the Royal Horticultural Society, with books on some popular and important plants in the pipeline. It’s not cheap, but even so I’m sure it won't make the RHS or its author much money. But it’s part of the role of the world’s largest and most prestigious gardening society to make fundamental information about plants available for the gardening and botanical community across the world. Count this as a job very well done.

Kniphofia: The Complete Guide by Christopher Whitehouse is published by the Royal Horticultural Society at £40.00/c$50.00.

* Disclosure: I was paid for a fee for a small contribution to this book.