American burnweed (Erechtites hieraciifolius), otherwise known as fireweed or pilewort, is a member of the daisy Asteraceae family. It’s a plant that is native to America (both North and South), however, it can also be found worldwide. This is mainly because it has been introduced to places like China, Hawaii, and Southeast Asia by human activity. There are two varieties of American burnweed, (Erechtites hieracifolius) can be found in clearings, fields, and disturbed sites all over New England as well as in most of North America; and (E. hieracifolius var. megalocarpus), which can be found exclusively around the edges of the salt marshes and on sandy beaches from New Jersey to Massachusetts.
It’s also an annual herb that has simple alternating simple leaves of 30 to 200 mm that are serrated and growing on a thick green stem. The leaves seem to resemble those of wild lettuce, which happen to be part of the same family of plants. They bear flowers in the fall that are either pink or yellow, and they often grow in clumps made up of multiple stems. The blooms have clusters of silvery hairs that are attached to little seeds. Burnweed is known to be native to the North American forest zones and can grow to be eight to ten feet high in ideal growing conditions. When the plant or its flowers are crushed, they smell quite unpleasant.
A very interesting thing about this species is that it actually benefits from fire, hence the nicknames “burnweed” and “fireweed.” Because of that, it can often be found in recently burnt areas. On the other hand, it does prefer moist areas but can also grow in gravelly soil and dry conditions to some degree. In addition, it can grow fairly well around people and in urban areas. Pollination of burnweed flowers is done mainly by wasps. Seeds are then dispersed by the wind and are utilized as a food source for many birds. Burnweed actively competes with many crops, including strawberries and blueberries, making it a nuisance weed for many property owners and a good reason for effective weed control.
Burnweed is one of those weeds that grow so quickly that it seems to just show up in your yard overnight. That’s because it’s a fast-growing weed that is commonly found in fields and gardens, especially around West Virginia, from late August to early September. Weed control can be fairly easy, however, using cultivation, hoeing, herbicides, or just pulling them out by hand. Burnweed is a benign weed to some extent and pulling it by hand is made easy by its shallow roots that are attached to a brittle taproot that is fairly short. Larger areas of this particular weed can be controlled with the application of a broadleaf herbicide that contains 2,4-D and triclopyr, or non-selective herbicides, like glyphosate or glufosinate. Be sure to start by first checking the herbicide label to determine the specific turfgrass tolerance and application rates prior to use, especially when attempting lawn treatment.
In addition to being a highly invasive weed, burnweed has a number of medicinal properties. The oil of the plant has been used for treating wounds, poison ivy rashes, hemorrhaging, and some other ailments, like piles. The plant is also efficient at the assimilation of atmospheric nitrogen dioxide (a greenhouse gas), rendering it back to the organic form of the gas.