Perennials are plants that live for more than 2 years, often for many years. Most woody plants and many herbaceous plants are perennials.
As a group, they are the most versatile plants in any landscape. They can thrive in every sort of soil from wet to dry and rich to poor, and in every exposure from full sun to shade. Some perennials flourish alongside streams or in the dappled shade of trees; others grow happily in meadows or in problem areas such as hillsides, steep embankments, and rocky outcroppings.
Adding even a few perennials to a dull landscape can transform it into an attractive garden. Perennials, given the little extra care they need at planting time and during the fall and winter months, reward the gardener with spectacular spring and summer displays, year after year.
Since most perennials are dormant during the winter, the only care they require is a bit of cleanup late in the autumn, some attention to over-wintering pests, and perhaps a mulch to carry them through the winter in climates where winters are extreme.