What's going on with my Hot Chocolate?

Can anybody tell me what's going on here then?

My Hot Chocolate is very strange indeed, one half of the plant looks normal, but rather small:



The other half has a tree growing out of it:



But, it has a massive collection of buds on the top of it waiting to bloom!



Why has it done that then? Is it okay?

TIA

 

did you prune unevenly and leave one large stem?

 

I don't think so, it looked fairly even at the beginning of the year. This one stem practically shot up over night!

 

Looks perfectly normal and healthy to me. Sending up new canes rapidly from the base is what a lot of roses do when they are growing strongly.
Next Spring you will prune them back to about a foot to 18 inches above the ground.