Hummingbirds are attracted to many flowering vines, but they seem just the right scale for cypress vine, which is covered with tiny white, bright red, or pink flowers in mid to late summer. Red flowers are the most common, but some seed companies sell packets of mixed colors. Cypress vine will twine up strings, cover a trellis, or scramble over shrubs; give it room to grow. It blooms best in areas with hot summers (and can self-sow invasively). The wispy, feathery foliage looks delicate, like tiny palm fronds, but the plants are tremendously heat- and drought-tolerant.
More vines for hummingbirds: Cypress vine is sometimes confused with cardinal climber (Ipomoea x multifida), which also has small red flowers. Cathedral bells, hyacinth bean, and morning glories attract hummingbirds, too. Shepherd's favorite hummingbird vine is scarlet runner bean. It does not bloom in the heat of summer, but it's pretty in fall or spring, and the beans are edible.