Striving to promote the well-being of
our North
Oregon Coast


Japanese knotweed control program ongoing in Manzanita, OR.

  Please do not cut, mow, or otherwise disturb knotweed!  If cut, dry thoroughly and burn. 

         DO NOT COMPOST !!  Please do not dispose of at Cart'M Recycling center.

                      Direct-stem injection shows results within weeks after treatment.


                    Knotweed colony prior to treatment                        After treatment, leaves are discolored and falling from plants.

   Mowing of knotweed induces increased shoot production and invigorates colony.

Consider our program of direct-stem injection before attempting to mow your knotweed.


This area was previously mowed and cleared to ground level.  These photos show the vigorous regrowth from knotweed's root system. 

Each stem cut resulted in several new shoots appearing.  The rapid speed of this regrowth can even be as much as 3' of growth in only two weeks.

Mowing of existing knotweed appears to be the worst method of control, as it quickly grows back more numerous and agressive.

The vigorous nature of this weed allows it to spread great distances underground to form new colonies.


The knotweed in these photos reveals how far it can grow underground before resprouting.  An existing patch of knotweed is growing over 50' away, in the distance due right of the garage.  It has grown underground and is penetrating through inches of asphalt to resprout.

If you identify a new colony of knotweed within the city of Manzanita, you may contact

Manzanita Public Works Dept. at 503.368.5347.

Outside of Manzanita, please contact David directly by email at,

or at 503.349.9984.