One of the best vines for growing on a wooden porch railing or post is clematis. Unlike some vines that become invasive and can damage wood structures, clematis is relatively easy to control, so you can train it to grow along the portion of your porch that you prefer. Clematis produces dark green foliage and large flowers in a variety of colors, including red, blue, white, pink and yellow. It grows well in USDA Hardiness Zones 4 to 9, but prefers a quick-draining soil. Full-grown clematis vines can vary in height from 6 to 15 feet.
The black-eyed Susan vine also provides attractive flowers for your wood porch. Its blooms are usually yellow, but you can also find varieties with white and orange flowers as well. Despite its colorful flowers, the plant gets its name for the distinctive dark centers in the middle of its blooms. A full-grown vine can reach heights between 6 and 8 feet, and may be grown in containers if you don't want to plant it in the soil next to your porch. Black-eyed Susan is hardy in Zones 4 to 9, and prefers sun or partial shade.
The purple bell vine is ideal for growing around wood porch railings and posts. A perennial vine, it has twining stems, heart-shaped leaves and bold, purple flowers. It can grow up to 10 feet in height, and prefers full sun to partial shade, along with rich soil. The purple bell vine is hardy in Zones 6 to 10, though it usually best to start the plant indoors and move it outdoors after the last frost of the spring. Once it's outside, you can train the vine to wrap around your porch railing or a trellis on your porch.
For an exotic addition to your wood porch, consider growing the passionflower vine. It is known for its extremely showy flowers, which come in a range of colors that include purple, blue, yellow and white. The vine can grow up to 10 feet high, and produces green fruit in the summer as well. Passionflower vine grows extremely quickly, and is hardy in Zones 7 to 9. However, if you live in a northern climate, you may grow it as an annual.