Twelve hundred years ago I lived in Kentucky and across from the house where I stayed there was a large south-facing slope that got really hot and dry. There grew a yarrow which was only about 10" tall and formed big salmon orange clumps. Some individual clumps were pure white, but not very many. I remember it very vividly because I used to pick the flowers to display on my lime green wall and it looked gorgeous.
I'm wondering if anybody is aware of dwarf varieties that might fit this description? Of all the "dwarf yarrow" varieties I've googled, they all appear to be yellow or too tall. It may have grown there for years and years. I don't remember anybody ever mowing or maintaining that area, and I heard only through the grapevine that a house had once been there. It was beside a burned down mosque and crumbling parking garage so until it was recently developed (i.e. student housing put there), it probably grew unencumbered for ages.