Most of this plant is about 1 1/2' tall but one shoot is about 2 1/2' tall. I am in Zone 4. It is in a garden that only has perennials.
It may be Amaranthus tricolor... there is a lot of variation in this species. https://www.google.com/search?num=10&hl=en&site=imghp&tbm=isch&source=hp&q=Amaranthus+tricolor