(1)    Definitions. In this section:

      (a)    “Nuisance weeds” means purple loosestrife or hybrids thereof and multiflora rose.

      (b)    “Purple loosestrife” means any nonnative member of the genus Lythrum.

   (2)   Prohibition. Except as provided in sub. (3m), no person may sell, offer for sale, distribute, plant, or cultivate any multiflora rose or seeds thereof.

   (2m)   Control efforts.

      (a)    Under the program established under s. 23.22, the department shall make a reasonable effort to develop a statewide plan to control purple loosestrife on both public and private lands, as provided in this subsection.

      (b)    The department shall make a reasonable effort to implement control and quarantine methods on public lands as soon as practicable. The department shall make a reasonable effort to employ the least environmentally harmful methods available that are effective, based on research conducted under sub. (3m).

      (c)    The department may conduct a pilot project using employees or other persons to engage in labor intensive efforts to control purple loosestrife on all public lands.

      (d)    The department shall request permission from private landowners to enter onto the land to control stands of purple loosestrife which significantly threaten environmental resources or which threaten to invade a nearby watershed or subwatershed. If the landowner denies the department permission to enter onto the land, the department may not enter the land but shall inform the landowner of the seminars available under sub. (4) (c).

      (e)    The department may provide grants to other public agencies to allow the public agencies to control purple loosestrife on lands under their control.

   (3m)   Research. Under the program established under s. 23.22, the department shall make a reasonable effort to conduct research to determine alternative methods to contain and control purple loosestrife in the most environmentally sound manner and may conduct other research on the control of nuisance weeds. The secretaries of natural resources and of agriculture, trade and consumer protection may authorize any person to plant or cultivate nuisance weeds for the purpose of controlled experimentation.

   (4)   Education.

      (a)    Under the program established under s. 23.22, the department shall make a reasonable effort to develop a statewide education effort on the effects of nuisance weeds, as provided in this subsection.

      (b)    The department shall make a reasonable effort to educate the authorities in charge of the maintenance of all federal, state and county trunk highways and all forest and park land in this state on methods to identify and control nuisance weeds. The department of transportation and all other authorities in charge of the maintenance of highways, forests and parks may cooperate with the department in efforts under this paragraph.

      (c)    The department shall make a reasonable effort to educate private landowners on methods to identify and control purple loosestrife. The department shall make a reasonable effort to conduct seminars periodically, at times determined by the department, to train private landowners in environmentally sound methods to identify and control purple loosestrife.

   (5)   Penalty. Any person who knowingly violates sub. (2) shall forfeit not more than $100. Each violation of this section is a separate offense.