Weed Alerts

March – Callery Pear and cultivars

Early April – Garlic Mustard

April/May – Pull Invasive Seedlings

June – Control Invasive Trees

July – Japanese Stiltgrass

August – Ailanthus (Tree-of-Heaven)

October – Invasive Bittersweet and a To Do List in our newsletter


Invasive Species Alerts

Early Detection Rapid Response (EDRR)

Lesser Celandine – Photo from OSU Extension

Lesser Celandine – Invasive Alert

Also called Fig Buttercup, this plant has been discovered in Greene and Albemarle Counties. Livestock that graze on fresh leaves of buttercup family plants, including lesser celandine, can become ill. It looks a bit like the common buttercup. The foliage sprouts from underground roots and tubers and appears in late winter before anything else greens up.


Water Chestnut

Localities, pond management personnel, and the general public are asked to look for a new species of Water Chestnut, Trapa bispenosa or two-horned water-chestnut, recently found in the Potomac Watershed. It has been spreading since 1995 so you may have already encountered this floating aquatic vegetation growing over the surface of a pond, lake or other freshwater bodies.

This species of water chestnut is identified by the seed cases having two spines instead of four found in the Eurasian water-chestnut. Reports of this or other invasive aquatic species can be made via the US Geological Survey Nonindigenous Aquatic Species web page.

Water Chestnut (an annual) will sprout in April and May, spread over the water surface and then flower and fruit by July; it drops seeds all season until it senesces after a hard frost. To stop the spread, management by harvesting the plants before July is very successful in eradicating the plants but it may take several years of effort if some seeds lay dormant. Early detection helps reduce removal costs and ecological impacts.

Distribution map (Trapa bispinosa)

For more information contact Nancy Rybicki, Aquatic Plant Ecologist with USGS.


Image: Penn State University


Spotted Lanternfly – Invasive Alert

The Spotted Lanternfly (SLF), Lycorma delicatula, is an invasive planthopper that was first found in the U.S. in 2014 (Berks County, PA). SLF was found in Frederick County, VA in January 2018 and is a threat to the local agriculture industry as well as the quality of life for area residents. SLF has a wide range of host plants (70+) and feeds on a variety of fruit and ornamental trees.  A quarantine was established by VDACS in early June 2019 for the City of Winchester and Frederick County. The quarantine requires business owners to obtain a permit and inspect all materials that are stored outside as well as trucks, trailers, and vehicles that travel outside of the quarantine area. Learn more about SLF and how to report a sighting at Virginia Cooperative Extension’s webpage.