Have done it , no problem, with pot plants. nursery tape and chlose pins, you gently bend it over. Use strips of panty hose 1/2 in , this prevent the porblem of string etc , as it dispersed the area. With string or wire you can cause the restriction on the stem, thus slowing down the vertical size.
I have even bent them in loops in a test. Always bend over a large radius and always have tape handy in case you break a stem or two. You realy gota be board to do loops with plants,
Just because the top of the plant is pointing down ,,,, does not make the plant grow upside down. (thats a joke)