What is a weed? The standard dictionary definition is “a valueless plant growing wild.” The so-called weed above appeared in one of our ornamental gardens several years ago. I didn’t buy it or grow it from seed, it just appeared, and I liked it, so I didn’t weed it out. It is a purple aster (Machaeranthera canescens), and it appears in one of my favorite identification books, Weeds of the West. The authors of that book have a better definition: “A plant that interferes with management objectives for a given area of land at a given point in time.” They point out that “some plants poisonous to livestock are considered desirable ornamental plants.” So in this case a weed was transformed into a beautiful ornamental plant.