Most annual vines thrive in hot summers. Sweet peas are the exception. "They need to be planted when you start your very first vegetables in the garden," Shepherd says. "They like cool weather, and they are brought into bloom by lengthening days." She recommends planting sweet pea seeds at the same time as parsley or lettuce. Be patient; the seeds may take several weeks to germinate. Sweet pea vines have little tendrils that grip a string, wire, or netting, and plants grow to about 6 feet tall in a sunny or partly shaded spot. The more the ruffled, fragrant flowers are cut for bouquets, the more lustily they bloom. In hot-summer climates, try starting sweet pea seeds indoors in late winter and moving the seedlings into the garden in early spring. Do not plant the seedlings deeper than they are growing in their pots.
More fragrant vines: Moonflower (Ipomoea alba) and cup-and-saucer vine or cathedral bells (Cobaea scandens) both have fragrant flowers and bloom in summer.