Submitter does not have a specimen
EDRR Status: Population treated
purple flowered head on plant about 1-2 feet tall, growign on banks of ponds. ID not in doubt; we know this plant!
Some plants could easily be seeding within days if not already. A senior citizen/botanist who lives at Willamette Oaks, has called the city twice now and they simply say they've put in an order, but they are clearly not responding in a timely manner to keep this invasive from spreading!