IF THERE IS one item common to every gardener's bookshelf, it is the "Sunset Western Garden Book," a classic since it was introduced in the 1930s. I bet whatever edition you have, even if it is the most recent one from 1995, it is dog-eared, with turned-back pages and smears of soil.

The good news is that there is a brand new, fattened up and completely revised edition fresh off the presses. The bad news is that it is so handily and expertly expanded that no matter what edition you already own, you'll want a copy of this new one.

The heart of the book is the 8,000-listing plant encyclopedia. Thousands of new plants have been added, so for a couple of years anyway this will be the best reference for the newest and hottest cultivars. You'll find the popular annual bacopa (Sutera cordata) is now available with golden foliage or lavender flowers. The section on salvias has color photos and is greatly expanded; and there are new kinds of apples, lavender and rhododendron.

What makes this book so useful is that all these new plants were compiled not as a result of one grower or designer's enthusiasm, but by surveying hundreds of nurseries all over the West to see what plants are available to the public. That is why we carry this book under our arms while we plant-shop: These are plants we can actually find, then learn to site and care for from the encyclopedia. This had been made easier by a new feature: a prominent information box to show exactly what plants need to thrive. Readers can see at a glance whether a plant is a good bet for their gardens.

Now In Bloom Hyacinths spread their heady perfume around the early spring garden. Their fat, stiff stems can be hard to site; they look their best clustered in single colors around doorways or in pots or window boxes. Hyacinths need sun and good drain-age, but will take partial shade. Hyacinthus orientalis 'City of Haarlem' is a bright yellow, 'Carnegie' a pure white. Both show up well against springtime greens.

Editor Kathleen Brenzel compares her year-and-a-half task of revision to conducting an orchestra. Her core staff of 10 worked with experts all over the West. Extension agents, nursery owners, growers and climatologists contributed. More weather data is available than in the past, so climate-zone maps have been refined, with microclimates pinpointed as much as possible. Hawaii and Alaska are included for the first time. Also emphasized in this edition are potential invasiveness (especially in Hawaii's hospitable climate) and responsible sources for native plants.

As with many an old friend, we tend to take the "Sunset Western Garden Book" for granted, forgetting the wealth of information between its pages. Gardeners often come to the library where I work, looking for CD-ROMS to aid them in finding plants ideal for special circumstances. All they need to do is turn to the front of this book to find comprehensive and knowledgeable lists for special situations - hardy plants for tropical effects, for example, or deer-resistant plants, or the best plants for windy or soggy places.

And you can forget all the tedious tomes on plant nomenclature, because in the back of this book is all you need to know unless you're really into taxonomy. A section on demystifying plant names lets readers in on the information to be learned from scientific names; the glossary explains things like palmate leaves and what in the world underplanting really means. An index to common names aids gardeners of every vintage. For someone like me, who knows all the plants my mother grew by their common names, and all the plants I've learned in the last 10 years by their scientific names, such an index is invaluable. As is this entire new edition which, with its drawings, photos and reliable expertise, earns its place on the desk and out in the garden.

Rhodies in the Spotlight
The Rhododendron Species Foundation's Spring Plant Sale will offer thousands of choice plants, and the Federal Way gardens will be open for touring, with rhodies and companion plants in full bloom. Friday, April 6, 3-6 p.m., and Saturday, April 7, 9 a.m.-3 p.m. Information: 253-838-4646.

Valerie Easton, a horticultural librarian who writes about plants and gardens for Pacific Northwest magazine, is the co-author of "Artists in Their Gardens" from Sasquatch Books. Her e-mail address is vjeaston@aol.com.