Plumbago auriculata (or Plumbago capensis) is a near-perfect plant to grow in Riverside County, California because it loves the sun and once it is established is drought-tolerant. Even easier to clone than lantana, and less toxic (no thorns, either), it flowers abundantly, and when not in bloom has attractive foliage.
Other common names include skyflower and cape leadwort.
I blogged about Plumbago Oct 3, 2009 and Oct 7, 2009
