Besides being an asset in the perennial border, ruellias definitely shine when planted as a mass or as accent plantings. They are both larval and nectar sources for butterflies, but I have not witnessed that for myself yet. The ruellias that will be for sale at your nursery later this spring are definitely perennial in zone 8, and people have told me they return in northern Mississippi in zone 7 with a good layer of mulch for winter protection. They are also easy to propagate. You can divide clumps, root cuttings and plant by seed.
Stems are easy to root in moist soil or sand.
Another big plus is that they are disease and pest free unless I coax a butterfly's offspring to munch on one. Recommendations on this web site do not endorse any commercial products or trade names.