For the first year your biggest issue is the root growth. They won't grow much vertically until they develop roots, but they'll easily spread within a few years to popping up all over. My 3rd year are now about 4' in each direction from the initial rhizome planting.
A tomato cage would work, if you're just looking to prove them out this year and then transplant the healthiest in the fall to a dedicated garden space. For anything after 1st year that tomato cage will be outgrown within about 2 weeks.