Place the trellises close together for maximum mass and privacy. Angle them like half-open shutters to soften a corner of your yard. Or, put them in parallel rows to make an open-roofed arbor.
1. Begin construction by cutting a 30-degree angle at the top end of each 2x4 post. We used a power miter saw for all cuts but the radius. Cut the two 1x2 brackets; nail each one to the inner face of a post, centering it side to side and with its top end 1-1/2 inches from the angled cut.
2. Create pointed tips for each of the 1x2 trellis uprights with 45-degree cuts, then cut the uprights to length. Crosscut the 1x2 trellis rails, then nail the trellis rails and uprights together into a lattice assembly.
3. Cut the 2x4 top rail to length; position it between the posts, and drive deck screws into countersunk pilot holes. Nail the lattice assembly to the brackets. Complete the assembly by cutting the roof pieces and screwing them into position.
4. For the arched trellis, cut the post tops square as shown in the detail drawing. We used a weatherproof carpenter's glue to join the 2x10s. We used a string and a pencil to draw the radius, and cut it with a saber saw.
5. Dig a pair of 28-inch-deep holes for each trellis. Four inches of crushed rock at the bottom of each hole provides drainage.