I'm not sure what that is but it's the same thing (or extremely similar) which grows in my garden every year and I try my best to weed it out before it goes to seed. To me it's just a weed. If someone else can identify it I'd like to know what it is too.

Looks like a run of the mill invasive exotic Mulberry seedling - Morus alba.

Things that sprout under a plant can just as easily come from bird droppings as from plant droppings.

Thank you for your comments re: weeds and mulberry seedling. I realize it could have come from bird droppings, that's how a wild blackberry bush showed up years ago...

I had hoped that it might be a red cherry tree, as our neighbour just on the other side of the fence has one. The leaves seem to look quite similar, except I cannot see the leaves of the neighbor's tree close up...

Yes, Mulberry.

when you break down the pot ... you will probably notice its yellow roots ...

plant the trees in dormancy.. after leaf fall .. in the fall.. mark them well ..

in many places ROS is somewhat in invasive ... or at least free seeding a bit much.. as evidenced by these that seeded themselves under the momma shrub.. do ask yourself.. if you really want to encourage such free seeding.. by adding more ROS around your yard ...

ken

Thanks for the advice! The mulberry shrub is already disposed of, and yes, I did notice the yellow roots!

We were planning to move this year ( which got delayed ) hence the plant in the pot, for the new place. Yes it self seeds here as the soil under this shrub allows it. However at my mom's place her rose of sharon was on the front lawn surrounded by grass, never an issue with self seeding and spreading. That's the any way to go in future.