The runners are usually above ground, though i've found some appearing several feet away because they snuck underground to get there.
The one I have in the back yard was started against a clothesline post, good strong support. The one in the front yard was started on broom handle, which rotted away into oblivion, so it now supports itself, albeit crookedly. When we had the ice storm 2 years ago, I thought I'd lost it, but no, it just leaned a little to the right. I propped it up again with rocks beneath the leaning part. So yes, it's best to start with a support then keep the support there while you continue to wrap the runners. I'll try to remember to get a picture of that trunk today, the one that has embedded itself within the clothesline pole.
