Ask-a-Dave's-Gardener: Need help locating a perrennial, 2 by Hvogler

Hvogler wrote:
I have been looking for the past few years for eight o\'clocks. They are yellow, and usually 10-12\" in height. They only bloom at eight o\'clock so my grandmother called them eight o\'clocks. My hubby pulled them from my garden a few years ago thinking it was a weed and i have been trying to find more ever since. Everyone is saying they may be 4 o\' clocks but really not sure. My mother said they can multiiply by tubers. Can anyone help me on where i can find?