The global horticultural trade in ornamental plants is well known to be a primary source of non-native invasive plant introductions worldwide. In the United States, non-native species make up as much as 80% of the ornamental nursery stock and account for most nursery revenue. Although only a small percentage of these species escape cultivation and become invasive, the large number and diversity cultivated, especially in California, results in ornamental plants contributing to more than half of the invasive weeds currently damaging California's wildlands and remnant natural areas in urban landscapes.

The majority of ornamental plants are purchased and grown by the public. Thus, educating consumers to make informed choices towards...

The United States Department of Agriculture (USDA) Delta Region Areawide Aquatic Weed Project (DRAAWP) has, as one of its purposes, to enhance and implement the rollout of new, innovative, or unique processes to support finding and controlling aquatic invasive species. It is using that overarching theme that the process described below was conceived.

Weed mapping researchers have long sought methods to better quantify floating aquatic vegetation (FAV) using global information systems (GIS) within specific areas. California State Parks Division of Boating and Waterways (DBW) manages aquatic invasive species on 69,000 acres of the Sacramento-San Joaquin Delta. DBW has identified more than 300 treatment sites in a multitude of...

From the Pest in the Urban Landscape blog • June 6, 2018

When people think of parasites, often what comes to mind are blood-sucking insects like bed bugs, head lice, and fleas or other bodily invaders on or in humans and other animals. But plants can have parasites too. Most of us are familiar with mistletoe but there is another parasitic plant you may not have heard about:...

Recently I was a participant on an educational noxious weed tour in Sierra Valley. It is a beautiful mountain valley where most agricultural production is devoted to grazing and hay production. The tour was set up by the Plumas Weeds group, to show land managers and ranchers various noxious weeds which are invading Sierra Valley. We discussed identification, biology, and control options for a variety of weed species. One of the questions which was inevitably brought up for each species was: “How long is the soil seed life of this weed?” This question led to interesting conversations.

When we stopped to look at hoary cress (Lepidium Draba) we had a relatively optimistic conversation. Hoary cress is a B list...