Perennials that may seem impossible to grow in the ground become easily cultivated in pots.
For instance, gardeners living east of the Mississippi will find the use of containers as a great way to expand their palette of perennials. This is especially true when it comes to growing xeric plants that would be unhappy in the ground because of excessive moisture and soggy freeze-thaw conditions in spring. I can't recount how many gardeners have asked me how to grow Agastache (Hummingbird Mint) in cold, moist, midwestern or eastern climates. The answer: plant them in pots. The same goes for growing Lavender, native Sage (Salvia greggii and hybrids), and other popular xeric plants!
Conversely, Western and dry-area gardeners may use containers to grow selected plants that require richer soil and more frequent watering.
Containers are also a great way to grow perennials that aren't quite winter-hardy enough for in-ground cultivation in your region. For example, gardeners in Zones 4 and 5, fcan enjoy Perennial African Daisy (Gazania), native Sage cultivars/hybrids (Salvia greggii), and Spanish Lavender (Lavandula stoechas) by planting in containers and overwintering the plants indoors.