Remember those barberry hedges we see too often? Is Oregon grape a close relative? Your guess could be as good as any ones! Some botanists put this in the same genus, Berberis. Others separate it into Mahonia. One of those cases where it is genuinely hard to know where to set the limits. This native is attractive enough to tempt us to grow it. But like its invasive hedge relative, that's now a no no. It's a host to black stem rust, a serious disease of wheat. Creeping Oregon grape grows in AZ, CA(E), CO, DE, ID, IN, MI, MN, MT, ND, NE, NM, NV, OR, PA, SD, TX, UT, WA, WY, AB, BC, and ON. Sites east of the Rockies are escapes. Lenawee Co MI, 3/29/12.