With a trumpet-shaped bloom and a dark eye, Thunbergia alata ‘Lemon Star’ sparkles with its velvety yellow petals. Also called Black-eyed Susan vine, this native of Eastern Africa is often seen for sale in hanging baskets in greenhouses. Don’t hesitate to use it, however, as an annual climber, much like you would a morning glory. T. alata can reach up to 8 feet in length under the right conditions, and it will blossom all season long with a profusion of sunny flowers set amid delicate-looking foliage. Give it something to climb on if planted in the ground or in a container.