A perennial plant is a plant that lives more than two years, unlike annuals and biennials which are short lived plants.
Perennials can be grown in raised bed gardens with no limitations. Most varieties adapt easily and will thrive so long as care is taken to protect the plant during times of frost.
The garden looks absolutely neat. The walls keep soil in place without spilling all over and pathways can be easily cleaned.
They require less struggle in terms of bending, more so for tall gardeners. This also applies to people with disabilities. They are more comfortable to use.