Incredible little bordering plant with cheerful bright yellow blooms in the late Spring.  Woolly Yarrow stays low to the ground.  Foliage is silvery gray, tended and fuzzy.  Spreading ground cover that will naturalize, so you will want to divide clumps every 3 or 4 years.  Drought tolerant as well as deer tolerant.  Plant in full sun for the best blooms but Yarrow can also take a bit of shade.  Make sure soil is well drained and is able to dry out in between waterings.  Good for rock gardens.  Use as a foreground to Salvia, Encelia, Pennisetum, and other natives.