What are perennials?
Perennials are persistent. These plants are not completely killed over the winter. A few may be evergreen, but most die back to the ground. Underground, perennials have different mechanisms for surviving the frozen winter. If the plant is hardy enough, it will re-grow when spring arrives.
Spiderweb sempervivum
How long do perennials last?
Different perennials have different life spans. Some are very long lived, others are short lived. Then there are biennials, using the first year to get established, flowering the second season to create a crop of seeds for reproduction, and then dying. Foxgloves are an example. A good strategy for keeping these popular biennials in your garden are to buy plants the first couple of years, and then let natural re-seeding maintain your population
Single hollyhock
Do perennials flower all the time?
Very few perennials flower all season.
Perennials can reproduce by increasing their clump size, or sending runners out under the ground, or just living a long time so that if seeds don’t make it one year, they can try again the next.
Mountain bluet
Penstemon Iron Maiden
Since survival of the species is not as dependant on seeds as with annuals, perennials don’t need to spend as 
much time and energy flowering.
Usually, perennials have a bloom season of a few short weeks. To get a continuously blooming garden, you need to plant different perennials with a succession of bloom times.
A few perennials may flower the first year, but many just build foliage to get established the first year, flowering the second year and thereafter.
Doronicum (Leopard’s Bane)
When is the best time to plant perennials?
You can plant perennials almost any time of the year that you can work the ground. You just need to leave sufficient time—usually several weeks—for the plant to take hold and get established before winter arrives.
I can plant a Perennial Garden and then just be done with it, right?
Perennial gardens will still need weeding, and once a perennial bed is planted you can’t till the whole thing
every year to knock down weeds. Perennials may need to be divided as they grow larger and thicker. Many gardeners enjoy the tendency of perennial gardens to evolve over time.
Can I mix annuals and perennials in the same garden?
Yes. You can even mix vegetable plants into a flower bed.
Cone flowers and rudbeckia daisies
(we cheated a little – they’re both
perennials)
