The only reason I am kicking myself is because there were so many other seeds I wanted to get and got those instead!Yes, that's purslane. Don't kick yourself. I have it growing wild and grew some from seed this winter too. You gotta have a variety seeds for zone 4, pretty mamma!
FYI: It's edible for humans too! There are many parts of Europe that sell this in the green markets. It tastes really good. -Kind of like a celery with a really pleasing texture. We use it all the time. Don't feel bad if you have too much...you can find lots of uses for it