It is spreading all over my yard, but I can't get its name right.
I'm used to calling it Oregon grape, but in fact, the one on the Front Range in Colorado is not really Oregon grape. The usual Oregon grape is Berberis aquifolia. It is Berberis repens that is common in Colorado. Common names for this plant include creeping hollygrape, creeping barberry, creeping mahonia, and creeping Oregon grape.