Yellow Starthistle is a plant of Old-World origin that arrived in California in the mid 1800's. It is believed that it made its way to California in contaminated alfalfa seed from Europe. It is one of California's worst noxious weeds, infesting parks, rangelands, pastures, hay fields, orchards, vineyards, canal banks, roadsides, and other disturbed areas. Since its introduction, yellow starthistle has spread steadily and now infests nearly 15 million acres throughout the state. Disturbances created by cultivation, poorly timed mowing, road building and maintenance, or overgrazing favor this rapid colonizer. It forms dense infestations and rapidly depletes soil moisture, thus preventing the establishment of desirable species. The spiny...

From roadsides in the city of Fresno to the oak woodlands in nearby Sequoia National Park, annual barleys and bromes are going to seed. In addition to a variety of other grasses, I often hear landowners, weed managers, pet owners, and veterinary advice blogs call these species "foxtails". This common name is applied to so many species that if someone tells me they have a foxtail issue, I have to ask to see it so that I know what species we need to manage.

Image: Hare barley in the spring, with fluffy spike seedheads.

The term "foxtail" also means different things in different contexts*. In the veterinary context, the term "foxtail" typically describes a grass seed that has barbed...

One response to the suggestion that an herbicide be used to control aquatic weed problems in water is concern that the treatment will reduce the dissolved oxygen content of the water, with possible adverse effects on fish and other aquatic biota.  In fact, some herbicide formulations even have warnings on their label to only treat one-half of a pond.  However, a recent study on treating water hyacinth (Eichhornia crassipes) in the Sacramento-San Joaquin River Delta demonstrates that a decrease in dissolve oxygen is not necessarily the outcome after an herbicide treatment.

Study sites were selected based on sites with water hyacinth growing along channels, and sites in which the water hyacinth grew in sloughs...

This article from the Sacramento Bee describes the impact of annual grass weeds on sites in the Great Basin, and argues that herbicides can play a role in salvaging the local ecosystem. Another entry in the category of "Ecology is complicated."