What is this flower?
This is a serious noxious weed - very, very invasive!! It is called Policeman's Helmet (Impatiens glandulifera). The Oregon Department of Agriculture has listed it as a Class B Noxious Weed. You should pull all of them immediately and dispose of them in the garbage. Do not compost the plants or seeds. Do not let them go to seed. Land conservancies and other land managers are going to great lengths to remove this significant invasive plant from Oregon lands. Please do not help this plant spread!!
Here is the weed profile from the Oregon Department of Agriculture.