- Arbor Day Foundation guide to tree requirements, hardiness zone maps, tree identification guide, tree care, a pruning guide and other tree related information
- BBG’s Online Library of Gardening Information a comprehensive library of autoritative gardening information including articles and tips organized by subject–from the Brooklyn Botanic Garden
- Container Gardening information on container and small space gardening from Colorado State University
- Cornell Garden-Based Learning The Garden-Based learning program at Cornell University provides resources for homeowners, schools and community groups who are interested in growing food and flowers and attracting wildlife.
- Department of Botany, Smithsonian Institution online versions of publications, references and tools, and photographs and botanical illustrations
- Gardening a comprehensive collection of information on all aspects of gardening from HGTV
- Gardening Resources information on vegetables, flowers, fruit, lawns, trees and shrubs and houseplants from the Horticulture Department at Cornell University
- Hunt Institute for Botanical Documentation history of botany and all aspects of plant science, includes beautiful images–from Carnegie Mellon University
- National Gardening Association a wide array of useful gardening information including a plant finder searchable by color, hardiness, light, etc. and a kids’ section
- Plants Database information from the Natural Resources Conservation Service of the United States Department of Agriculture about vascular plants, mosses, liverworts, and lichens
- SelecTree: A Tree Selection Guide information on 1,400 trees–options for searching to generate a list of trees with certain attributes such as height, water and soil requirements–from the Urban Forest Ecosystems Institute
- UConn Plant Database of Trees, Shrubs and Vines browse by Latin or common name, search for plants, a plant selector and virtual plant walks
- Vegetable Garden Intensive Gardening Methods harvest the most produce possible from a given space–from the University of Arizona
- What Tree Is It? identify trees by leaf, fruit or name from the Ohio Public Library Information Network
