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About Noxious, Controlled & Poisonous Plants

Agriculture is critical to Pennsylvania and we enjoy our rich landscapes and beautiful natural resources for outdoor recreation and way of life.

However, in order to protect Pennsylvania's agriculture and ecosystems we must be knowledgeable of and aim to prevent the spread of noxious and poisonous plants and ensure that controlled plants are regulated.

In March 1862, the first noxious weed law was enacted that included Canada thistle, chicory, Johnsongrass, and marihuana. 

In April of 1982 the law was updated to include multiflora rose and established a committee to update the law with plants as needed.  The law also defined a noxious weed as "a plant that is determined to be injurious to public health, crops, livestock, agricultural land or other property" and noted that "it shall be a violation of this act to sell, transport, plant, or otherwise propagate the weed within the Commonwealth."

In October 2017, Governor Tom Wolf passed The Controlled Plant and Noxious Weed Act. The law places weeds in three classes based on spread and eradication potential and includes the Federal Noxious Weed list by default as Class C weeds.    

Controlled plants are a plant species or subspecies that is regulated to prevent uncontained growth and to negate undesirable characteristics and require a permit to be grown in Pennsylvania.