Ipomoea

A fast, twining annual vine from tropical America grown for the azure-blue trumpets that open at dawn and fade by afternoon, each marked with a white-to-golden-yellow star throat. Heart-shaped leaves clothe stems that climb 8 to 10 feet in a single season on any support. Showy and easy from seed, but every part - especially the seed - is poisonous if eaten, so site it away from where pets and children graze.

A tender, tuberous-rooted morning-glory relative native to tropical America and cultivated for its starchy edible storage roots for over 2,000 years. Trailing stems mound only about 9 inches tall but sprawl 8 to 10 feet wide, rooting at the nodes, with heart-shaped to palmately-lobed leaves. The species occasionally bears pale-pink-to-violet trumpet flowers, though most cultivars rarely bloom. Winter hardy only to USDA Zones 9-11, it is grown as a warm-season annual everywhere colder.