Annuals:  These are the plants that need to be planted every year as they do not come back after the winter.  A common misconception, plants including pansies, violas, dianthus, and snapdragons, are not perennials.  They are annuals.  These annuals are very hardy and may come back or may reseed themselves, but because they are not reliable to come back for more than one or two years, cannot be considered a perennial.
     Annuals are perfect for planters, window baskets, or hanging baskets.  They offer color all summer long, and grow quickly.  They last the length of one season, and will be killed by a freeze.

Perennials: These are the plants that come back year after year.  Their hardiness is dependent on your zone, and plants chosen for the correct zone, will thrive and grow in size for many years to come.  Not all perennials bloom all summer long, and the description should be read for each plant to determine the blooming season.  Many perennials, including delphinium, make wonderful cut flowers.  
     Perennials should be planted only in the ground and not in planters or baskets.  Because of the constant freeze-thaw climate that we have during the winter months, our planters and baskets do not remain consistently frozen.  This thawing and refreezing of the soil causes the plants roots to rot, therefore killing the plant.  Perennials do need the moisture provided by mother nature all winter long and will not survive in a pot in a garage.
     Plants that can be taken in during the winter months, ex: geraniums and begonias, are not considered perennial.  Because they are actively kept alive or forced into dormancy, they are not perennial.  Plants that die with the frost and come up with in the spring are perennial.