Guide to Common Pennsylvania Weeds

Noxious weeds can be a gardener's worst nightmare. Here is a guide to getting rid of three common noxious weeds of Pennsylvania. These PA weeds include goutweed, garlic mustard and musk thistle.

Gout Weed - Common Pennsylvania Weed

Goutweed is a noxious weed commonly found in Pennsylvania. Goutweed is an herbaceous perennial plant that spreads aggressively by the root. Goutweed is also known as bishop's weed and snow on the mountain. Goutweed is found in several states including Pennsylvania, Connecticut, New Jersey, Michigan, Vermont and Wisconsin. Small patches of goutweed can be eliminated by carefully hand pulling or digging out the patches. It is important to eliminate the root of the plant to ensure that the plant does not grow back. For goutweed, that has infested lawns or roadside areas, short mowing can help control growth. Systematic herbicides such as glyphosphate (Round Up) are the most effective way to control this noxious weed common to Pennsylvania.

Garlic Mustard - Common Pennsylvania Weed

Garlic Mustard is another noxious weed common to Pennsylvania. Garlic Mustard is also found in more than thirty states throughout the United States. This prolific biennial herb spreads aggressively in woodlands by seed. During the summer and fall of its first season, garlic mustard appears as small green rosettes, which resemble violets. If you are able to properly identify garlic mustard at this stage of the growth, eliminating now is optimal. During spring of the second season a two to three foot flowering stalk will appear. The goal in containing garlic weed is to prevent seed production. For that reason it is best to pull out the plant or cut the stalks before the flower appears. It is also possible to get rid of garlic mustard by using an herbicide like Round-up. It can take several years of treatment to remove large growths of this noxious Pennsylvania weed.

Canada thistle, Musk Thistle and Bull Thistle

These three varieties of thistle are also common Pennsylvania weeds. Bull thistle is a biennial noxious weed that prefers sunny open areas. This Pennsylvania weed has a two-year life cycle. Bull thistle can be manually removed by digging the plant up. It is only necessary to remove the top couple of inches of root to kill the plant and eliminate further spread of this Pennsylvania weed. Close cutting twice per season is another way to eliminate seed production and prevent further spread.

Canada thistle is an aggressive creeping perennial weed that infests crops, pastures and roadside areas. The best way to eliminate Canada thistle is to stress the plant by returning the area to its natural use. Planting another strong crop in the area can help stress and kill out Canada thistle.

Musk Thistle is another variety of thistle that is a Pennsylvania weed. Musk thistle is an aggressive biennial weed that reproduces from seed. In order to control this noxious Pennsylvania weed you need to control the seed production. Herbicides such as tordon, milestone and transline can be effective at eliminating this Pennsylvania weed.

Sources:

http://www.dcnr.state.pa.us/Forestry/wildplant/invasivelist.aspx

http://www.nps.gov/plants/alien/fact/aepo1.htm

http://www.finegardening.com/how-to/qa/removing-invasive-garlic-mustard.aspx

http://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/weed-identification/bull-thistle.aspx

http://www.ext.colostate.edu/PUBS/NATRES/03102.html