I saw this on our walk today – it seems to grow freely along the sidewalk around here. I have found out that it is "Purple Dead-nettle, Lamium purpureum, a non-native Eurasian weed in the mint family" (from this link), and that it apparently grows wild in many places across the United States.
Seeing this made me remember that there are many types of plants that you would not buy as landscaping or groundcover plants, but they are very pretty and do make excellent borders. Several herbs come to mind in this category, such as the flowers produced by plants such as cilantro and chives, as well as bush-type legumes, such as the soybeans I am considering planting on the border of my yard this summer.
