Tropical, sub-tropical and tender perennials are all classifications of outdoor plants that handle heat well. Most often, these plants bloom with vibrant colors during the summer and reappear season after season.
For colorful flowers all summer long, plant cannas outdoors in full sun. There is a wide variety of Canna species to choose from, all of which are tropical or sub-tropical and handle the heat well. Cannas are grown from bulbs, or rhizomes, and may stand up to 8 feet tall in your garden. Hardy from zones 8a, cannas have brightly colored flowers and large foliage ranging from bright green to variegated blue-green. Cannas prefer slightly acidic to neutral soil that stays moist but that drains well.
Tropical hibiscus plants grow best in full sun and are perennials in zones 9 and above. You can also grow these outdoor plants in containers and bring them indoors during colder climates, or plant them as annuals. Hibiscus plants will bloom most often if you plant them primarily in full sun with partial shade during the hottest part of the day. Keep the soil around the moist, but well drained. Organic compost mixed in with the soil and a layer of mulch around the plants will help the soil retain moisture.
Lantana plants may be tropical, tender perennials or annuals, depending on where you live, but they will produce colorful blossoms repeatedly, all summer long. Lantana is considered invasive in some parts of the U.S. and all parts of it are poisonous if ingested. The plant may grow up to 4 feet tall and attracts birds, butterflies and bees. Plant lantana in full sun, water it often and it will handle the heat well in zones 9b and higher.
Passion flowers are native to the Southeastern U.S., but they also thrive in other parts of the country. Another name for this distinct flowering plant is maypop as they seem to burst forth in early May. The blooms begin in July and continue until the first frost. Passion flowers are grown on vines that can grow up to 15 feet in one season. Passion flowers also produce edible fruit that is often used to make jams and jellies. Plant your passion flowers in full sun and keep the soil moist, but make sure that it drains well. Hardy in zones 5 through 10, maypops will die back after the first frost, but will reappear the following spring.