Weed A plant that grows vigorously in spite of efforts by the farmer to control it. It may crowd out desirable plants or choke out crop fields. It may also produce seeds that disperse and grow in new areas. Often, farmers will use chemicals to try to control weeds.

UC IPM Weed Photo Gallery

A searchable database of photos of many, but not all, weed species found in California farms and landscapes. The site allows you to check features of a particular weed such as whether it has a stem or leaves that are simple or broad. Then, it will eliminate all weeds that don’t meet those criteria.

The database includes pictures and a description of each weed as well as its natural habitat, growth habit, sex, and other important characteristics. It is very helpful in identifying specific weeds.


The app enables you to upload photos of plants from your smartphone or tablet and share them with other users around the world. The app also lets you create a list of observations and provides data on when and where you saw certain species of plants, including weeds.

Invasive Exotic Weed: Plants that are non-native to an area and lack the natural enemies that curtail their growth and spread. Classic examples are kudzu and English ivy. Many invasive exotic weeds are targeted for regional or nationwide coordinated eradication efforts. Examples of these include field bindweed, quackgrass, yellow nutsedge, and buckhorn plantain.