An arbor can not only provide a good habitat for climbing plants such as wisteria, it can add a unique and beautiful accent to your garden or shelter a pathway. You can easily construct arbors from any sort of structural wood, but it will last longer if you use a rot-resistant wood, such as cedar. You can customise an arbor for a climbing wisteria or another climbing plant to match the decor of your house or yard.
Dig four holes 2 feet deep by 1 foot in diameter. The holes should form the corners of a rectangle approximately 2 feet wide by 4 feet long. Orient the long sides so they are the entrance of the arbor, and you'll want to dig the holes so that the two sides of the arbor can be set parallel to one another.
Place 6 inches of 3/8-inch gravel at the bottom of each hole.
Put the 4-by-4 posts in the hole, and use foundation stakes to support them as you check to make sure they are level. Once the posts are level, pour in the concrete, and wet according to the manufacturer's instructions. Allow the concrete to dry for at least a day, or as the instructions for your brand of concrete dictate.
Remove the foundation stakes from the bottoms of the posts.
Cut the 2-by-6 board in half so that you have two 5-foot lengths. Each of these will form one of the crossbeams for the long side of the arbor, with about 6 inches of overhang on each side.
Temporarily nail the crossbeams to the top front of the posts so that the crossbeams face out and their top edges are flush with the tops of the posts. Check to see that they are level, and then drill two holes through the crossbeams and each post for the 3/8-inch lag bolts.
Secure the crossbeams to the posts with the lag bolts and nuts, and remove the temporary nails.
Cut the 2-by-3 board into four equal lengths of 30 inches each. Secure them at equal intervals, suspended above the two crossbeams, nailing them through the top with the 10d nails. There should be about 2 to 3 inches of overhang on each side of each of these arch beams, which you can detail to match your decor or provide some flair to your arbor design.
Place the wisteria cuttings in a bucket of water mixed with the rooting hormone (dilute according to manufacturer's instructions). The cuttings should form root balls in two to three weeks.
Dig a 6-inch hole next to each side of the arbor, and plant the root balls in each hole, mixing the existing dirt with peat moss for nutrients. Water thoroughly. Once sprouts emerge, guide them toward the posts, and they will climb up as they grow.