I love sweet woodruff - but it does not naturalize here in our heat and summer drought. I've grown it before (at another house in this area) and it required a loamy raised bed and frequent irrigation just to survive. My whole yard is under trees that are pretty evenly distributed throughout the property. Vinca is fine, and I am planting it bit-by-bit along a long, exposed clay bank on one side of the property, but would not want a large yard covered with it.