Perennial flowers will just stay for Spring and Summer. In Autumn and Winter they will disappear and appear the nest Spring. It is just a normal cycle for plants.
perennial
One perennial flower is the impatien.
Each variety of perennial blooms at different times.
Most Lillies grow from a bulb so they are perennial flowers.
Perennial, but most die in the winter
I have always preferred perennial flowers over annuals.
Most Lillies grow from a bulb so they are perennial flowers.
Lithadora
Iris is a perennial so it will winter over.
The type of flowers that bloom every year without replanting includes perennial flowers. Roses, Plumbago, and hibiscus flowers are all examples of those perennial flowers.
Columbines. Columbines are beautiful and easy to manage. They attract humming birds too! Or if you don't like them, use this link to see a whole list of perennial flowers you can choose from. http://home.howstuffworks.com/perennial-flowers.htm