A few months ago, I was asked about the toxicity of various plants in a horse pasture after the death of a miniature horse using that pasture. While many of the identified plants were chemically harmless (such as filaree [Erodium spp] and some native clovers), the pasture did have fiddleneck (Amsinckia spp) and popcorn flower (Plagiobothrys spp), two native forbs with potentially toxic chemistry.

Popcorn flower (above) has small white flowers. Fiddleneck (below) has slightly larger yellow flowers. Both plants have similar overall shapes: slender flowering stems, relatively small leaves, and hairs on all parts except the flowers themselves.

Fiddleneck is a known...

From the Lassen county Farm Advisor's Update newsletter (Aug. 2020)

Highlighting Two Uncommon Noxious Weeds
Let's keep them uncommon!

There are two species of noxious weeds I want to bring to your attention, as they are not that common in our area: rush skeleton weed (Chondrilla juncea) and sulfur cinquefoil (Potentilla recta). Both of these perennial species have relatively small populations in the Intermountain...

Perennial pepperweed (Lepidium latifolium) also known as tall whitetop is a root-creeping perennial weed. It is commonly found along roadsides, ditches, and drains. It is also a big problem in pastures, non-cropland, and even cropland that is not tilled on a yearly basis. Unlike many other weeds of the state, pepperweed is problematic throughout many ecotypes, from low elevation wetlands around the delta up to high elevations in the Sierra's. Perennial pepperweed spreads by seed and root fragments and is very persistent and difficult to control once established.

Up in the Klamath basin, I've been amazed at the number of perennial pepperweed patches flowering along the road and ditches this year. The plants' tiny white...

Wildland herbicide applicators in California have to be licensed or have be supervised in the field by a licensed applicator. The California Department of Pesticide Regulation (DPR) requires all license holders to complete continuing education hours every two years and the amount depends on the license type. Most wildland herbicide applicators have a QAL or QAC license and for those license types DPR requires 20 total hours of CE every two years with at least 4 hours of laws and regulations hours (however please review the DPR website for complete information because there are some exceptions (https://www.cdpr.ca.gov/docs/license/liccert.htm and see here for general...