Amra, thank you for your question to "Ask Extension".  I believe, based on the photos submitted it is Sorbaria sorbifolia (false summac).  It is described as a coarse shrub grows to 5 to 8 feet tall (sometimes to 10 feet) and as wide. It displays masses of tiny white flowers in early summer when mature and the deep green foliage resembles mountain ash to which it is related.  It reproduces vegetatively by underground suckers and also by seed.  Intensive root pruning can be used to control the spread, the key word is INTENSIVE getting as much of the root system as possible.  Another procedure that was mentioned was cutting the main stem as close to the ground as possible and immediately apply a systemic herbicide to the cut end of the stem with a paintbrush.  A good time to treat would be in the fall when the reserves are going back down into the root system.  It is not on the Oregon noxious weed list nor on the Oregon invasive species list.
     I hope that you find this information useful and as always Happy Gardening.