Hi Nan, and a big
to ATP.
Would love to see a photo of your purslane, there are so many different types. The culinary type comes back every year for me in my zone 8, but I know it comes back from self seeding in much colder zones.
Is your the ornamental type? You can save seed from it for next year. They start very quickly from seed.
We do have some in our database.
http://garden.org/plants/searc...
I don't even have any of the ornamental type in my yard, but this year a beautiful plant started growing at the foot of the steps to our deck. I'll have to get a photo of it tomorrow. It had to be brought in by a bird.