Broadleaf Weeds | University of Maryland Extension

Updated: October 31, 2024

Marestail: Identification and Management in Nursery and Landscape Settings

Marestail (Conyza canadensis), also known as horseweed or Canada fleabane, is a common winter or summer annual broadleaf weed found in nurseries, greenhouses, landscapes, roadways, meadows, turfgrass, and crops. It is problematic due to vast seed reproduction in two cycles, wind dissemination, lack of seed dormancy, and adaptability to both moist and dry soils.

Updated: October 30, 2024

Common Groundsel: Identification and Management in Nursery and Landscape Settings

Updated: October 30, 2024

Control of Large Palmer Amaranth and Common Ragweed in Soybean or Corn (FS-1192)

Herbicide-resistant Palmer amaranth and common ragweed are two weed species that pose a major challenge to farmers. It is recommended that an effective postemergence herbicide be applied before these weeds are 3- to 4-inches tall. Palmer amaranth and common ragweed plants that exceed this height are challenging to control. This report summarizes research and discusses the challenges of managing large Palmer amaranth and common ragweed plants. Authors: Kurt Vollmer, Michael Flessner, Dwight Ligenfelter, Vijay Singh, Mark Vangessell, and John Wallace. Title: Control of Large Palmer Amaranth and Common Ragweed in Soybean or Corn (FS-1192)

Updated: October 24, 2024

Iron-based Herbicides

An examination of the efficacy of iron-based herbicides. These selective, broadleaf herbicides contain the active ingredient chelated iron.

Updated: October 24, 2024

Japanese Stiltgrass Identification and Management

Now is the time to scout pasture and hay fields for Japanese stiltgrass and take note of its locations. This invasive grass is typically seen in wooded areas, but unfortunately has been creeping into fields. Once the seed heads start to form in another month or two, you’ll want to have the mower ready.

Updated: October 24, 2024

Assessing Herbicide Options for Preplant Weed Control in Soybean

Starting clean, or weed-free, is a critical component of any weed management program. In 2022, growers experienced either a lack of or higher cost of glyphosate-based herbicides that are typically used to control weeds prior to planting soybean. In a study sponsored by the Maryland Soybean board and conducted at the University of Maryland’s Central Maryland and Wye Research and Education Centers, different glyphosate-based and non-glyphosate based herbicide treatments were evaluated for their ability to provide effective preplant weed control (Table 1). These treatments included both single and sequential herbicide applications.

Preplant application results using liberty and gramoxone.

Updated: October 24, 2024

Evaluating Late Season Burndown Options for Palmer Amaranth

A common question asked by farmers dealing with herbicide resistant Palmer amaranth is, “What are the most effective burndown options in situations where Palmer amaranth is larger then the ideal 3-4 inch control range?”