At this year's San Francisco Flower and Garden Show, the Sunset staff had put up a sign showing every edition of their famous "green book" going back to 1954. The caption asked, "Do you remember your first?"

I remember my first. It was the sixth edition, about 13 years ago. I was shamed into buying it by a garden center employee who rolled his eyes when it became clear that I didn't know what "the green book" was. "The Sunset book!" he said impatiently. "How can you not have one?"

The guy might have had a little to learn about customer service, but he was right. How could I not have a copy of the most authoritative book on gardening in the west? Now that I'm a garden writer, it's a professional necessity. If I mention an unfamiliar plant in an article, the editor might call me and say, "What is this plant? I can't find it in Sunset ." If it's not in Sunset - well, you'd better explain yourself.

So that was my excuse for rushing right out and buying the hefty, $35 book as soon as it was released. It's a business expense, right?

The new edition covers 500 new plants, bringing the total to 8,000. To make room within the book's 768 pages, some plants had to go, and the plant index disappeared altogether. (The book is organized by species name, so the index was handy if you only knew a plant's common name.) When I talked to an editor at the garden show, he explained that the index was already integrated into the encyclopedia: If you're looking for mint, just look it up alphabetically, and you'll see a note referring you to Mentha, the plant's species name. This works well for specific plants, but just try looking up "grass." You'll find an entire essay on the species names of various plants that we think of as grass, and it's sandwiched between Graptophyllum pictum and Grevillea.

The editors also added short sidebars on the care and feeding of some of the most popular plants in the book. Junipers, for instance, get four pages of charts listing 86 varieties, and after that, a sidebar explains their sunlight, soil, water and pruning needs. For most gardeners, that's all the information you'd need to satisfy your juniper jones.

The book still offers good, detailed information on climate zones, and the plant selection guide continues to offer good recommendations for plants that tolerate damp soil or deep shade or prolonged drought or a number of other typical West Coast environments.

I was disappointed to see that, given the lack of space in the new edition, the editors decided to devote 18 pages to short essays by garden writers in each region. They're not useful as reference material; they're the sort of thing that you'd only read once. The photographs that accompany these essays are fantastic - Sunset knows its plant porn - but I would have rather seen the sections on each climate zone expanded to include more pictures, then forget about the cute little essays.

I also wish the editors would come up with some other way to organize the "Practical Guide to Gardening" in the back of the book. I'm glad it's there - by including some basic gardening information, this book really can be the only book a beginning gardener would need - but organizing the topics alphabetically means that, for instance, Composting is found between Bulbs and Container Gardening, not near Mulch or Soil where it should be. It would not be difficult to come up with a better arrangement and include a short table of contents at the beginning of the section.

But that's a minor complaint. It's great fun to have a new "Green Book" and in fact, I've already taken it out into the garden and smudged some dirt on a couple of pages. If you have a seventh edition that's in pretty good shape, you wouldn't be missing out on too much if you just decided to stick with what you have. But if you're a couple editions behind, or if your book is a little too well-loved, it's time to upgrade.

You bought the book -- now go buy some plants. Humboldt Botanical Garden Foundation is holding its annual plant sale on Saturday, May 5, at the garden's northgate entrance on the College of the Redwoods campus. If you're a member, you can show up at 8 a.m. and grab the good stuff. Otherwise, you've got to wait until 9. The sale runs until 2 p.m., and I've always found great plants there.

Also, don't miss the North Coast Chapter of the California Native Plant Society's Spring Wildflower Show at the Manila Community Center on May 4-6. This free event runs Friday from 1-6 p.m., Saturday 10 a.m.-6 p.m., and Sunday 10 a.m.-4 p.m. On Friday, Rick Tolley will host a free drawing workshop, and on Saturday there will be workshops on identifying wildflowers and local shrubs, and a dune walk. On Sunday, you can learn about medicinal uses of native plants and about wild edible plants on the north coast. And of course, there's a plant sale all weekend. Call 822-2015 for details.