This is a groundcover used in frost free areas. I've seen it with frost burn in SoCal but rarely. It grows in sun or part shade to only 6" high but as much as 6' wide. I've always known it as Pink Clover. But I've read it to be called Pink Knotweed, Pinkhead Smartweed and I'm sure there are more names. The botanical name is Polygonum capitatum. This photo was taken at one of my jobs in Pasadena. It is spilling over a rock wall. I've always thought the cute pink fowers look like the puff from Dr Seuss' "Horton Hears A Who" on which the whole land of Whos live. The plant can be a weed to those who don't want it. Groundcovers travel and therefor often grow to compete or swallow up other plants. Keep it contained and enjoy the cute little flowers of Pink Clover.