Creeping Buttercup is a widespread invasive in Washington state. It can spread up to 40 ft a year and depletes soils of potassium, harming nearby plants. Easily recognized by its shiny yellow 5-petaled flowers and parsley-like leaves. 

To remove Creeping Buttercup, pull up by the roots. Be sure to bag and dispose of everything as they can regrow from stem or root fragments. Mowing is ineffective due to their short height. 

(Image credit: King County Native Plant Society)