I picked up a regular Martin Frobisher in a clearance sale. The main
cane was straight and tall around 4'. I trimmed off branches. It
looked like a rose tree. I call it poor man's rose tree.

I put it in a 7 gallon plastic pot. It looked nice. I'm thinking about
getting more of them.

Question 1: Can Martin Frobisher be trained as a tree?

Question 2: Is Martin Frobisher grow well in a container? (I know it's
not optimal condition for rose in a container. I just want to survive
and bloom some)

I'm in zone 5.