From ThisOldHouse.com comes a DIY on creating your own Trellis in a Pot.
Step 1. Put in the largest supports
Insert four tall branches firmly around the edges of a container filled with rich potting soil. Beech branches are especially graceful, but any woody plants with lots of side branching—butterfly bushes, Japanese maples, birch, high-bush blueberries—can be used.
Step 2. Add smaller branches
Insert smaller branches into the soil between each of the large ones. Any that are too short to meet at the top can be woven in. Make sure there are plenty of fine twigs for tendrils to grasp. Weave in or snip any that stick out.
Step 3. Tie the top
Gather the tallest branches near their tops and tie them together with twine. Stand back and take a good look. Adjust the top if the whole structure leans. Tuck in any unruly branches or cut any outward-facing ones.
Step 4. Fill in
Insert another round of little branches to fill in any holes. Tuck in, tie, or trim stray twigs on the inside, as needed. Plant sweet peas (or other vines). Thyrza also plants the center with lettuce, which fills the space quickly and can be harvested before the sweet peas take over.
Photos and DIY via ThisOldHouse.com