Useful Weed Identification Tools

The UC Statewide Integrated Pest Management Program's website contains many useful features to help identify pests and problems in the garden and home. One such feature is the Weed Gallery, which contains hundreds of images and management tips for more than 150 common weeds found in California.

If you don't know what weed you are dealing with, the gallery will help you identify the plant using visual characteristics. First, narrow your search by selecting the weed category—broadleaf, grass, sedge, or aquatic plant (Figure 1). You will then see a collection of photos in that category.

Select the appropriate plant characteristic (Figure 2) to see another sub-menu of weeds that exhibit the traits of your weed. Scrolling over a thumbnail image on this sub-menu will bring up several photos of the weed—as a seedling, as a mature plant, its flower, and its seeds—to further aid in identification (Figure 3).

Once you think you've identified the weed, click on the link of the weed's name, which will take you to a photo gallery page where you can read about the weed's habitat, growth characteristics, and life stages (Figure 4). For many weeds, there is a link to a Pest Note that provides information about management, both chemical and nonchemical. In addition, each page in the gallery links to the Calflora website to show where the weed grows in California.

If you think you know the name of your weed, the gallery allows you to quickly access photos using common or scientific names to confirm identification. Just use the “List of All Weeds” link from the main weed gallery page.

The gallery contains other features as well:

• Want to know more about plants and their parts? Illustrated tutorials distinguish among broadleaf, grass, and sedge plants and define plant parts used in characterizing certain plant species.
• Need to identify common weeds found in lawns or turf? The broadleaf and grass categories link to a dichotomous key, where users can pinpoint common turf (and landscape) weeds.
• Didn't find your weed? See the weed identification tool under “More information” to search the UC Weed Research & Information Center (WRIC) technical weed key.

You can access the weed gallery page from the left-hand column on many pages on the UC IPM website or from the various weed-related pages within the website. To access the weed gallery directly, visit http://ipm.ucanr.edu/PMG/weeds_intro.html.