Source: Gardner's Path
Beloved by many gardeners for its heat tolerance and shade-loving nature, but reviled by others for its eagerness to spread with abandon,R. simplexcan be divisive. Thanks to its sweet purple flowers, however, we come down firmly on the pro-ruellia side of the debate.
With forms tall and short, this evergreen, herbaceous perennial — hardy in USDA Hardiness Zones 8-11 — deserves consideration for inclusion in southern gardens. The tall version forms clumps 18 inches across, while the short type forms 12-inch clumps.
It’s an erect, often-multi-stemmed plant with dark green, droopy, slender, and long leaves. It’s especially loved for its papery, trumpet-shaped flowers that mimic every shade of the purple rainbow, as well as white and pink.
Sadly, each lovely flower lasts just a day. But fret not — the plant produces a succession of profuse two-inch flowers daily from spring through fall.