A helpful directory of online plant databases, primarily in the United States and Canada, for information on plant names, growing zones, research, and images to help ID plants.
Also see Seed Company Listings for the United States and Canada to find a seller near you.
Plant Databases
North America
- All Plants | National Gardening Association Plants Database (US)
Search by characterisitcs, genus, and images - All Plants | USDA Natural Resources Conservation Service (US)
Includes common & scientific names, photos, growing zones - Identify Plants | Garden.org
Enter characteristics to identify your plant - Invasive Species | invasivespeciesinfo.gov (US)
Includes land and aquatic plants - Native Plants | North American Native Plant Society Database (North America)
Search by type, habitat, light, soil conditions - New England | Go Botany | Identify plants
- Trees | What tree is it? | (Based in Ohio, US)
Search by leaf, fruit, name - Weeds | New Jersey Weed Gallery and Is This Plant a Weed?
- Wildflowers | Lady Bird Johnson Wildflower Center (Texas, US)
Scroll to bottom of page for search box
Also
- Insects, Spiders, & More | BugGuide.net
Canada
- Invasive Species | invadingspecies.com (Ontario, Canada)
Includes terrestial and aquatic plants, fish, forest pests, invertebrates, and pathogens - Native Plants | Evergreen.ca (Canada)
Browse by region, name, characteristics, and plant type or species - Weeds | weedinfo.ca (Canada)
Search by broadleaf, grassy, and perennial weeds - Ontario CropIPM | broadleaf, grass, and perennial weed gallery
- Identify Seeds | Canada food inspection database with images
- BC Invasive Species | Includes plants, animals, fish, insects, and fungi
United Kingdom
- All Plants | UK – Royal Horticultural Society (UK)
Search by sun, soil, characteristics, plant type, or season
World Plants Database
- All Plants | canadaplants. ca (Canada and world) – link no longer active
Woody, bulbs, annuals, perennials, tropicals, wildflowers, and weeds
Seed Companies
- Canadian Seed Company Listings | Online sellers
- United States Seed Company Listings | Online sellers
Reference Book
Encyclopedia of Plants and Flowers | Amazon
Find Your Frost Dates & Hardiness Zone
- Plant Hardiness Zones |
United States | 
Canada
These are listed on seed packets and plant tags to guide your choices.
- Average Frost Dates | Use this calculator at Almanac.com. Enter your city and state or province to find your first and last frost dates and number of frost-free days.
Plants by Species / Type
- Garden.org Online Plant Databases – all plant types
Includes listings of online plant databases for specific states, regions, and plant species.
Here are some popular ones:
- Clematis | Identify your clematis – good for figuring out which clematis you have
Also see National Gardening Association Clematis Database - Dahlias
- Daylillies
- Hostas
- Hydrangeas
- Irises
- Lilies
- Ornamental Grasses
- Peonies
- Roses
- Tomatoes | Cornell Database
- Salvias
- Sempervivium
- Wildflowers – Regional Listings
Plant Research & Evaluations
- Search | Google Scholar for research papers
- Search | Chicago Botanic Garden plant research and evaluations
- Search | University Extension research papers | Check that research is peer-reviewed.
- Reference | How to properly write plant names | PDF file
- The Global Seed Vault in Norway | Learn how it protects seed species from around the world
Plant ID Phone Apps
IOS and Android
The idea is great: use your phone to photograph a plant you want to identify and ask the app to ID it or narrow down the options (if it’s unsure).
I can’t say I’ve ever found a plant identification app that was accurate. Out of every 10 queries, perhaps 5 might be correct.
Also, a lot of these apps seemed to have moved to a paid model where there is a fee to either buy the app or request help.
After my last round of testing, I liked this one (somewhat):
Garden Answers | http://www.gardenanswers.com/
If you’ve found one you think is excellent, I’d love to know.
Related: How to Understand Plant Names | Botanical Latin
~Melissa the Empress of Dirt ♛
