White Yarrow (Achillea millefolium) is one of the easier perennial flowers to grow, establishing itself in a variety of different soil types and growing conditions. Yarrow will spread via rhizome, and can take over if conditions allow. This can be good thing, as the spreading habit can be utilized to outcompete aggressive weeds. We have noticed Yarrow outcompete Nutsedge (Cyperus sp.), establishing itself while the Nutsedge is dormant in the winter months.
Yarrow's tiny flowers that make up the larger flower heads are extremely attractive to beneficial pollinators: native wasps and bees, flies, butterflies, etc. Yarrow makes an excellent orchard understory plant and is considered to be a dynamic accumulator, mining nutrients from deep in the soil. It makes a great ground cover and replacement for lawns, standing up to minor foot traffic. On top of all of this, White Yarrow is just a beautiful flower.