In The Garden: Can you identify these plants found in this Toronto backyard?

I moved into this house and have no idea if these are weeds or plants I would want to keep. If you could identify these three that would be appreciated. Toronto, Ontario.

 

2, I fear, is Fallopia japonica, Japanese knotweed.

 

Thanks! please note the pictures are sideways, sorry about that - i dont know how to rotate them on the post. I think picture 1 and 3 are the same plant.

 

1&3 look like Philadelphus.

 

but it's not really bushy, nor did it flower. It's just thin and tall.

 

I thought Philadelphus as well.