Perennials have a life cycle of 3+ years, as opposed to "annual plants" (1 year) and "biennials" (2 years). Using life cycle as a criterion dispels 3 myths about what makes plants perennials:
- Myth #1: Perennials are hardy.
- Myth #2: Perennials die back in winter but return in spring.
- Myth #3: Perennials are the plants you see year after year in your garden.
Myth #1 About Perennials
It's true that, if you're successful at growing certain perennials in your region as perennials (i.e., they live 3 years or longer), then they must be hardy in your zone. But if you live where it gets cold in winter, many plants from warm climates that are properly classified as perennials will not last more than a year for you. When speaking of such plants, we often say they are "treated as annuals" in regions such as yours.
But this doesn't change their classification as perennials. They are merely perennials whose life cycle has been cut short.
Myth #2 About Perennials
Some perennials do die back in winter and return in spring. But that characteristic is not, per se, what makes them perennials. Only one category of perennials follows this pattern: the herbaceous perennials.
However, there is another category of perennials: the woody perennials. Woody perennials do not behave in this manner.
Myth #3 About Perennials
Just because you see "the same" plants in your garden year after year, they're not necessarily perennials. They could simply be re-seeding.
