Perennial are flowering herbaceous plants, meaning their stems are soft and fleshy, not woody as with trees and shrubs. These small flowering plants grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their root-stock. Herbaceous perennials survive degrees of winter cold by virtue of roots that are stronger and more vigorous than those of annuals. With the onset of cold, the tops of perennials die down but the roots