The term perennial usually refers to flowering ornamental plants that continue growing, blooming, and seeding for a number of years. Although many perennials are evergreen, some are herbaceous, which means that the leaves and stems die down to soil level at the end of the growing season. Not to worry! Their roots (tubers, corms, etc.) survive through winter and foliage grows back the next spring.
Most plants are marked with a zone number which corresponds with a region on a map where that plant will survive. While a range of zones might be listed, the lower of the zone numbers indicates the lowest recommended zone in which that plant can survive. Also note that what may be perennial in its place of origin may be considered an annual here in the Pacific NW.
Once a perennial is successfully established in your garden, you don’t have to replant every year. You can even divide and plant them in other areas of your garden or share with others.
Perennials are good teachers. Growing them over the course of several seasons allow you to learn what they like/don’t like, their growth patterns, time of bloom, good companions, etc. Perennial ground covers are perfect for controlling erosion and weeds and retaining moisture, and can even be great lawn substitutes. Plus, many perennials offer fragrance, make great cut flowers, and attract hummingbirds and butterflies to your garden.