Royal Catchfly (Silene regia) is a bit awkward when not flowering, but do not let that fool you. Hummingbirds and swallowtail butterflies flock to this species and a stand of Royal Catchfly can turn the eye from a great distance away. When Silene regia is a mature plant it grows up to 4' in height in very well-drained soil, but can grow in sandy soil and gravel as well.
The name catchfly comes from the fact that insects are often stuck all over the stems. A close look will reveal why. Sticky glands cover the plant and small insects alighting upon it often become fatally trapped.