A decorative garden arch is often built as a gateway to a garden or a path. You can build your own out of materials found on your property and craft wire wrapped in willow wands. With its wire-ladder sides, the four-post arch can also serve as a functional trellis for climbing vines, ivies, flowers or lightweight vegetables such as peas. For garden gateways, grow the plants in large pots at the foot of the arch. You can also install the arch in your garden and plant climbers in the ground at the arch base.
Select your garden arch's corner posts from limbs or trees at least eight feet long and four inches in diameter. With a saw, trim any offshoot branches. Leave notches and forks in place.
Measure an area on flat ground where you want to install your decorative garden arch. Place garden rocks as post markers.
Dig the four corner post holes at least 24 inches deep. Excavate the soil. Shovel about six inches of pea gravel into the bottom of each hole.
Install the posts into the post holes. Fill the holes with pea gravel around the posts, leaving about three inches at the top. Top off the post holes with excavated soil until level with the surrounding ground.
Tamp the posts in firmly.
Clip four lengths of flexible craft wire, with each strand about six feet long. Twist two lengths of wire together to form one double strand, six feet long.
Wrap the twisted wire around the top end of one of the corner posts. Secure the wire to the wood with staples.
Arch the twisted wire as you extend it diagonally to another corner post. Wrap the end around that post and secure with staples. Repeat the process on the remaining two corner posts so that the arched wires form an X.
Wire one end of a willow wand to each corner post. Wrap the willow wands around the wires, securing the wands with additional pieces of wire to the arches.
Clip six pieces of wire, each about 14 inches long. Staple the wires horizontally to connect the sides of the corner posts. Position three wires on each side to form a rough ladder up the sides of the garden arch.
Cut the remaining willow wands into 14-inch pieces. Cover the side wires with the willows. Secure the wands with additional wire.