I do give mine a wee bit of help, rather depends on what I want it to go up on. Thunbergia though as stated above will find it's way up anything it can twine around. Depending on what I want the vine on, I use a combination of little pea sticks and fishing line as I do for morning glories for my picket fence. If you're wanting to put it in front of say a privacy type fence you'd have to give it something to twine on. I use a black webbing (totally disappears) to get some annual vine coverage on a few areas of my privacy fence. I use little twisters that are clear plastic covered wires to very loose tie in place as things get started depending on what vine. Never tie tightly though you want nothing that will damage the vine and you have to remember the vine will be getting thicker as it grows.

Barbara, Is it a chicken wire type frame? Is it an upright rosemary? If so, I start trimming it while it is a small plant inside the frame so it will branch out better within the frame. It may take months to fill it in depending on the size of the frame and the plant. I think if you were to let it grow out of the frame and THEN trim it, you end up with a bare middle.

Since it's about the same tree as your other post you might want to put this question with the other post and delete this one.

Snipping plants is fine regarding roots roting. I've never half a problem. I think it's safe to do with any plant. Disturbing roots is more dangerous. A lot of plants will bounce right back, but some plants have delicate roots, and will either get stunted in growth for a while or even die. If the sowing instructions only say 'direct sow' without mentioning transplants, then you should only snip of the top on those you don't want to keep.