Question
are portulaca a perrenial?  

Answer
Hi Scott,
Thanx for your question.  Portulaca is an annual but I remember when I was a child, my great-aunt had it around her door way in a rural part of our city. As a child, it reminded me of desert plants and my great-aunt and my great-uncle had a home in an area that has sandy soil and in the summertime can appear like the desert. I remember how many people would comment on the flowers.  I have always loved portulaca since.  One thing to note.  My aunt's potulaca reseeded themselves for decades.  Just like my 4 O'Clocks do.  I hope this helps.
tom