Perennials are plants that survive frost and live in the ground for more than 2 years, as opposed to annuals and biennials which last for one and two years respectively. They are distinct from shrubs and trees because they have little or no woody growth. Herbaceous perennials are those perennials which, depending on the local climate, may bloom over the spring and summer, die back in the autumn and winter then re-grow from their root-stock in the spring.