
Here you will find a comprehensive list of weed identification resources for the USA and Canada.
Given the vast size of the continent and the tendency of weeds to be a local issue, the weeds of North America are many and varied.
The books on weed identification tend to focus on broader areas. Some of the web resources are more localised, as they tend to be university based.
I list the books first and the web resources after.
Weeds of North America – identification books
USA general
Published by the US Department of Agriculture, this well illustrated book covers 220 important weeds with illustrations, maps and botanical information:
Common Weeds of the United States
North/Midwest/Canada
A “manual for ready identification of 299 common and economically important weeds in the region south to Virginia, north to Maine and southern Canada, and west to Wisconsin”:
Weeds of the Northeast by Richard Uva
Weeds of the Northern U.S. and Canada by France Royer:
Weeds of the Northern U.S. and Canada: A Guide for Identification
Weeds of the Midwestern United States and Central Canada:
Weeds of the Midwestern United States and Central Canada
Northwest Weeds: The Ugly and Beautiful Villains of Fields, Gardens, and Roadsides:
Northwest Weeds: The Ugly and Beautiful Villains of Fields, Gardens, and Roadsides
Western USA
Weeds of the West by Tom Whitson:
Weeds of the West – Tom Whitson
Southern USA
Brush and Weeds of Texas Rangelands:
Brush and Weeds of Texas Rangelands
Weeds of the South:
Weeds of the South – Charles T bryson (Ed)
Weeds in South Texas and Northern Mexico: A Guide to Identification:
Weeds in South Texas and Northern Mexico: A Guide to Identification
Weed identification web resources
The US Department of Agriculture has an invasive and noxious weeds page. The weeds are organised state by state, with links to photographs and plant information for most of thew weeds listed by each state.
The Weed Science Society of America has a a list of common weeds of North America.
The problem with both of these resources is that they are organised by plant name. So, if you only know what the plant looks like, rather than what it is called, you need to trawl through the pictures one by one to find your culprit.
This weeds gallery at Photobar contains images of 293 common weeds, together with common names. Once you have identified your weed, you’ll need to search elsewhere for more detailed information about it.
The Weedalert website has some terrific information about control of individual weeds and is also organised into geographical regions. Again, though, you need to know the name of the weed before you start or your efforts will be a bit hit and miss.
This resource from the University of Illinois allows you to narrow down the choices by selecting different characterists of the weed you are trying to identify
Here is a helpful photo identification tool from the University of Minnesota.
Virginia Tech has comprehensive catalogue of weeds, listed by name and also an identification tool for grasses.
Martin Cole has been an avid plant lover and gardener for more than 20 years and loves to talk and write about gardening. In 2006 he was a finalist in the BBC Gardener of the Year competition. He is a member of the National dahlia Society.
He previously lived in London and Sydney, Australia, where he took a diploma course in Horticultural studies and is now based in North Berwick in Scotland. He founded GardeningStepbyStep.com in 2012. The website is aimed at everybody who loves plants or has been bitten by the gardening bug and wants to know more.
Gardening Step by Step has been cited by Thompson and Morgan, the UK’s largest mail order plant retailer, as a website that publishes expert gardening content.
Great set of resources. It’s really helpful to have all these in one place, especially links to the identification guides. Thanks