I noticed some Ornamental Rhubarb in Vancouver last fall and loved the huge leaves and fragrant tropical red flowers towering above. This variety below is good for zones 3-6, grows quickly to 6' tall and 6' wide in sunny areas or partly shady areas.
Great Gunnera is similar to the Ornamental Rhubarb. The leaves can grow to 5 feet across! The plant can reach up to 9' tall and 12' wide, grows quickly and likes full sun and lots of moisture!