Here are a few importand resources that I have located that can help you now and possibly in the future. There is also a Master Gardener Hotline available daily 
and here is the contact information for Multnomah County that may also be of assistance should this information be insufficient:
 <personal data hidden> also online at metromastergardeners.org 

Oregon Invasive Species Council: 100 most dangerous invaders to avoid  http://www.oregon.gov/oisc/Pages/most_dangerous.aspx#Land_plants 

Portland’s Invasive Plants (a poster) unique to our area. http://www.portlandoregon.gov/bes/article/98648  and an informative article from
 OSU Extension
 http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/22283/em9035.pdf  

Should you want to consider the relative safety of the various herbicides available here is a very useful website that enables you to serach for the least toxic products and their pros and cons.   growsmartgrowsafe.org