They Don't Need Replanting For Years

Perennial Plant is a plant that lives for more than 2 years. An annual flower only lives for one season or year and the biennials live for two years. Perennials are not related to trees or shrubs all those these also normally live for many years. 

Small flowering perennials that grow and bloom over the spring and summer often die back every autumn and winter then return are known as heraceous perennials. Tomato vines live many years in their tropical habitat but are annuals in this area because of the temperature does not allow them to survive winter. 

Evergreen perennials retain a mantle of leaves through the year. The local climate may dictate whether plants are treated as shrubs or perennials. In warm region they may retain their shrub name but in colder weather they may be cut to the ground due to winter frost.

Begonias are perennials and often found in flower boxes

golden rods are often found in open areas

mentha (mint) is also a perennial and can be found many different places

The agave is a perennial plant found in very hot areas . Each rosette blooms once and then dies

IF you are looking for plants to place in your garden that do not require planting each year take a look at perennials.