Gateways and sites providing information on a broad spectrum of gardening topics.
Cornell Gardening (Cornell University)
Broad spectrum of gardening information, photos, etc. Check out the plant guides.
Gardening (Purdue University)
Fact sheets and other information for home gardeners.
Home Gardening Site (USDA)
U.S. Department of Agriculture Home Gardening web site containing horticultural information, gardening tips, hardiness maps and other information
Horticulture (Texas A&M)
Offers a wealth of information on home lawn & garden topics. Of particular interest is the Earth-Kind section which identifies plants with the best drought, pest and heat tolerance to include Earth-Kind roses.
Lawn & Garden (Rutgers University)
Complete information on gardening and lawns