| Rating | Book | Author |
 (1) | Ideas for Great Backyard Cottages | Cynthia Overbeck Bix |
| Ideas for Great Patios & Decks | Editors of Sunset Books & Magazines |
| Identifying Ornamental Conifers: The New Compact Study Guide and Identifier | Richard Bird |
| Identifying Trees: An All-Season Guide To Eastern North America | Michael D. Williams |
| Ikebana: Step-By-Step Japanese Flower Arrangement | Reiko Takenaka |
| Illinois Bird Watching: A Year-Round Guide | Bill Thompson, III |
| (2) | Illinois Gardener's Guide | James A. Fizzell |
 (2) | Illinois Wildflowers | Don Kurz |
| Illustrated Guide to Pruning | Edward F. Gilman |
| Illustrated Handbook of Succulent Plants: Aizoaceae A-E | H.E.K. Hartmann |
| Illustrated Handbook of Succulent Plants: Aizoaceae F-Z | H.E.K. Hartmann |
| Illustrated Handbook of Succulent Plants: Asclepiadaceae | Albers, Focke; Meve, Ulrich (editors) |
| Illustrated Handbook of Succulent Plants: Crassulaceae | Urs Eggli (Editor) |
| Illustrated Handbook of Succulent Plants: Dicotyledons | Urs Eggli (Editor) |
| (1) | Illustrated Handbook of Succulent Plants: Monocotyledons | S. Arroyo-Leuenberger, et al (Editor) |
| Impatiens: The Vibrant World of Busy Lizzies, Balsams, and Touch-me-nots | Raymond Morgan |
| Impressionist Roses: Bringing the Romance of the Impressionist Style to Your Garden | Derek Fell |
| (2) | In a Canadian Garden | Nicole Eaton |
| In a Green Shade: Writings from Homeground | Allen Lacy |
| In Defense of Food: An Eater's Manifesto | Michael Pollan |
| In Harmony with Nature: Lessons from the Arts & Crafts Garden | Rick Darke |
| In Praise of Apples: A Harvest of History, Horticulture, & Recipes | Mark Rosenstein |
| In Praise of Plants | Francis Halle |
| In Pursuit of Plants: Experiences of Nineteenth and Early Twentieth Century Plant Collectors | Philip Short |
| In Search of Great Plants: The Insider's Guide to the Best Plants in the Midwest | Betty Earl |
| (2) | In Search of Lost Roses | Thomas Christopher |
| In Search of the Wild Asparagus | Roy Lancaster |
| In the Land of the Blue Poppies: The Collected Plant-Hunting Writings of Frank Kingdon Ward | Frank Kingdon-Ward |
| In Your Greenhouse: A Beginner's Guide | Greta Heinen |
| Indiana Gardener's Guide | Jo Ellen Meyers Sharp |
| Indigo Dying (China Bayles Mystery) | Susan Wittig Albert |
| (1) | Indoor and Greenhouse Plants - Vol 1 | Roger Phillips |
| (1) | Indoor and Greenhouse Plants - Vol 2 | Roger Phillips |
| Indoor Gardening: A New Approach to Displaying Plants in the Home | Diana Yakeley |
| Indoor Plants: Flowering and Foliage Varieties for the Home | Halina Heitz |
| Indoor Plants: The Essential Guide to Choosing and Caring for Houseplants | Jane Courtier (contributor) |
| (1) | Inner Gardening: A Seasonal Path to Inner Peace | Diane Dreher |
| Insect, Disease and Weed I. D. Guide: Find-It-Fast Organic Solutions for Your Garden | Linda A. Gilkeson |
| (1) | Insects and Gardens: In Pursuit of a Garden Ecology | |
| Insects of North America | George C. McGavin |
| Insects of the Pacific Northwest | Peter Haggard |
| (1) | Insects, Pests and Diseases of the African Violet Family | Nancy Robitaille |
| Inside Out: Decorating Outdoor Spaces with Indoor Style | Meredith Books |
| Intimate Garden, The Spaces That Surround and Nourish | Brian Coleman |
| Introduction to California Chaparral (California Natural History Guides) | Ronald D. Quinn |
| Introduction to California Spring Wildflowers of the Foothills, Valleys, and Coast (California Natural History Guides) | Philip A. Munz |
| Introduction to Forest Ecology and Silviculture | Thom J. McEvoy |
| Introduction to Permaculture | Bill Mollison |
| Introductory Plant Biology | Kingsley R. Stern |
 (3) | Invasion Biology: Critique of a Pseudoscience | David Theodoropoulos |
| (1) | Invasive Plants of California's Wildlands | Carla C. Bossard |
| (1) | Invasive Plants of the Upper Midwest: An Illustrated Guide to Their Identification and Control | Elizabeth J. Czarapata |
| (1) | Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species | Sylvan Ramsey Kaufman |
| Invasive Species in the Pacific Northwest | P.D. Boersma |
| IPM for Gardeners: A Guide to Integrated Pest Management | Raymond A. Cloyd |
| Iris | Theodore James |
| Iris (Gardener's Handbook, Vol 2) | Fritz Kohlein |
| (1) | Iris: Flower of the Rainbow | Graeme Grosvenor |
| Iris: The Classic Bearded Varieties | Claire Austin |
| Irises | Pamela McGeorge |
| Irises (RHS Wisley Handbooks) | Sidney Linnegar |
| Irises: A Practical Gardening Guide | Karen Glasgow |
| (1) | Italian Gardens | Judith Wade |
| Ivies (Little Plant Library) | Hazel Key |
