Begin Main Content Area

Controlled Plant and Noxious Weed Program Information

The Pennsylvania Department of Agriculture (PDA) regulates the Controlled Plant and Noxious Weed Control List and implements federal and state eradication and control programs.

Plant identification and information is also provided by PDA. In addition, PDA maintains the State Herbarium.  

Noxious weeds are placed within one of three classes, Class A, B, or C based on spread and eradication potential and includes the Federal Noxious Weed list by default as Class C weeds.    

Class A Noxious Weeds

Preventing new infestations and eradicating existing infestations of noxious weeds in the class is high priority.

Class B Noxious Weeds

The department may require control of Class B weeds to contain an injurious infestation or may provide education or technical consultation. 

Class C Noxious Weeds

Preventing introduction and eradication of infestations of noxious weeds in this class is the highest priority.  Class C noxious weeds are any Federal noxious weeds listed on the Federal Noxious Weed List that are not yet established in the Commonwealth and are not referenced on the Controlled Plant & Noxious Weed Lists page.

A controlled plant is a plant species or subspecies that has been designated by the committee as a controlled plant and is regulated to prevent uncontained growth and to negate undesirable characteristics.

Controlled Plants

Hemp - Cannabis sativa L and any viable part of that plant with a delta-9 THC concentration of not more than 0.3% on a dry weight basis.

Plants included on the Controlled Plant & Noxious Weed Lists has been voted on and approved by the Controlled Plant and Noxious Weed Committee and will become official 60 days after publication in the Pennsylvania bulletin.

Information on Pennsylvania's current noxious weeds is also available on the Resources page.

Questions regarding the control programs should be directed Trilby Libhart at or by phone at 877-464-9333 or to the Bureau of Plant Industry contact listed at PDA Regional Office near you.