We need your help - is there marijuana growing in our New Hartford backyard?

So, there I was - just weeding (no pun intended) our garden when I came across a plant I didn't recognize - except that it did look kind of familiar...from, like, pictures and stuff. Is there grass growing in our yard - I mean, there IS grass growing in the backyard - but is there grass? 

It has five leaves that are long and thin, and serrated along the edges. It look JUST like marijuana. (If the authorities are reading this, I only know what marijuana looks like because I looked it up. And I definitely didn't plant this. And if you want to come pull it out - be my guest. If you could mow the lawn while you're here - that would be great.)

When we asked on Facebook - because of course that's where you go when you think you might have an illegal drug growing in your background - there was a suggestion that we might be looking at something called "rough-fruited cinquefoil." And now that I look at the pictures - that makes sense.

Credit: By NaturKamera - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3818530

What do you think is growing in our yard? Weed weeds, or just regular weeds?