Canadian Horseweed in Howard Co., Maryland (9/13/2013).

View Record Details Photo by Bill Harms MBP List

Canadian Horseweed in Caroline Co., Maryland (9/14/2020).

View Record Details Photo by Jim Brighton MBP List

Canadian Horseweed on Assateague Island, Maryland (8/19/2012). This is an abundant roadside species in Maryland.

Photo by Bill Hubick MBP List

Canadian Horseweed on Assateague Island, Maryland (8/19/2012).

Photo by Bill Hubick MBP List

Canadian Horseweed in Prince George's Co., Maryland (8/18/2016).

View Record Details Photo by Bill Harms MBP List

Canadian Horseweed in Caroline Co., Maryland (8/23/2016).

View Record Details Photo by Wayne Longbottom MBP List

Canadian Horseweed in Charles Co., Maryland (9/25/2016).

View Record Details Photo by Wayne Longbottom MBP List

Canadian Horseweed in Allegany Co., Maryland (6/6/2015).

View Record Details Photo by Kimberly Booth MBP List

Canadian Horseweed in Allegany Co., Maryland (6/6/2015).

View Record Details Photo by Kimberly Booth MBP List

Canadian Horseweed in Caroline Co., Maryland (8/28/2016).

View Record Details Photo by Wayne Longbottom MBP List

Canadian Horseweed in Baltimore Co., Maryland (8/24/2016).

View Record Details Photo by Kirsten Johnson MBP List

Map Snapshot

448 Records

GA AL WA FR CL MO HO BA BC HA CE PG AA CV CH SM KE QA CN TA DO WI SO WO

Description

The nominate variety of Canadian Horseweed can be easily identified by checking to see if the phyllaries are green tipped. Differentiated from the pusila variety which has purple tipped phyllaries.

Relationships

Host plant for various species of moth including Wavy-lined Emerald Moth (Database of World's Lepidopteran Host Plants).

Seasonality Snapshot

Resources

View at iNaturalist View at Nature Serve Search Google Images Search MBP Facebook posts

View at Maryland Plant Atlas Search Flora of North America Search Mid-Atlantic Herbaria Consortium Search Norton-Brown Herbarium

Use of media featured on Maryland Biodiversity Project is only permitted with express permission of the photographer.

Canadian Horseweed in Howard Co., Maryland (9/13/2013). View Record Details Media by Bill Harms.

Canadian Horseweed in Caroline Co., Maryland (9/14/2020). View Record Details Media by Jim Brighton.

Canadian Horseweed on Assateague Island, Maryland (8/19/2012). This is an abundant roadside species in Maryland. Media by Bill Hubick.

Canadian Horseweed on Assateague Island, Maryland (8/19/2012). Media by Bill Hubick.

Canadian Horseweed in Prince George's Co., Maryland (8/18/2016). View Record Details Media by Bill Harms.

Canadian Horseweed in Caroline Co., Maryland (8/23/2016). View Record Details Media by Wayne Longbottom.

Canadian Horseweed in Charles Co., Maryland (9/25/2016). View Record Details Media by Wayne Longbottom.

Canadian Horseweed in Allegany Co., Maryland (6/6/2015). View Record Details Media by Kimberly Booth.

Canadian Horseweed in Caroline Co., Maryland (8/28/2016). View Record Details Media by Wayne Longbottom.

Canadian Horseweed in Baltimore Co., Maryland (8/24/2016). View Record Details Media by Kirsten Johnson.