- Adam Dimech’s Story of Flowers
- All-America Selections Winning Seeds
- American Daylily Society
- American Hydrangea Society
- American Orchid Society
- BugGuide ID
- Bumblebee.org
- Clematis International Society
- Cornell Woody Plants Database
- Dave’s Garden
- Fine Gardening Mag Online
- Garden Web Forum
- Gardenology.org Plant Lists (Search by zone)
- Herb Society of America
- Horticulture Mag Online
- MushroomExpert.com
- Paghat’s Garden
- Peony.org ID Utility
- Perennial Plant Assoc. Plants of Year
- Pollinator Partnership
- RHS Award of Garden Merit Plant Finder
- RHS Plant Finder
- The Butterfly Website
- The Pollination Home Page
- The Seed Site, devoted entirely to seeds
- USDA Plant Hardiness Zones
- Urban Gardens Web
- Weed Identification (Illinois C-FAR)