Add some color to your indoor space with these six beauties:

Hibiscus
Some gardeners consider hibiscus (Hibiscus rosa-sinensis) to be the queen of flowers. With flat blooms that can reach 12 inches across, depending on the cultivar, it's definitely a showstopper. Cultivars are available in a range of colors—yellow, red, orange, pink, purple, silvery-blue, and even bicolors.

Like most flowering plants, hibiscus needs plenty of light to produce blooms. Keep it well fed in spring and summer with a fertilizer formulated for blooming plants. While actively growing, water abundantly. In autumn and winter, water less, allowing the potting mix to dry slightly before you water the next time.

Calathea
Calatheas (Calathea spp.) look tropical, but aren't as flamboyant as many plants from warmer regions of the world. Their shiny, often-variegated leaves, on some types, are a foot long and nearly as wide. One of the more common types, Calathea sanderiana, has dark-green, nearly black leaves with narrow hot-pink stripes. Calathea ‘Corona' has olive-green leaves accented by dark-green edges.

Calathea thrives in a spot with moderate to bright light and abundant humidity. Be careful not to over-water it; let the potting mix to dry a bit between waterings. Fertilize in spring and summer with a foliage-plant fertilizer to keep leaves looking lush and healthy.

Angel's trumpets
With their huge, pendulous flowers (which may be fragrant, depending on the type), angel's trumpets (Brugmansia spp.) are loved by many gardeners. Because of recent interest in the plants, breeders have produced some spectacular showy specimens, including types with variegated foliage and blooms in shades of yellow, orange, peach, or white. One note: All parts of these popular plants are extremely poisonous.

Angel's trumpets like relatively warm days (65 to 70F) and cool nights (50 to 60F). To keep producing blooms, the plant also needs lots of light and abundant humidity. Take care not to over- or underwater—a stressed plant attracts pests, including spider mites, in hordes.

Coleus
Though it's often thought of as an outdoor annual, colorful coleus (Solenostemon scutellaroides) also shines indoors. A myriad of cultivars are available with foliage in shades of green, chartreuse, red, burgundy, and almost black. Many types have several colors present on each leaf. For example, a popular variety, ‘The Line', has golden-yellow leaves bearing a black-purple stripe up the center of each leaf.

Grow coleus in a bright spot and water when the surface of the potting mix begins to dry. Pinch the plant back frequently to keep it from getting leggy, or take cuttings and replace an old, stretched-out plant.

Bird of paradise
One of the most exotic and well-known tropical houseplants, bird of paradise (Strelitzia reginae) has fantastic orange flowers. When not in bloom, the gray-green, reed-like foliage is attractive, too. As they grow, the plants form tidy clumps similar to many cold-climate perennials that can reach 3 feet tall or more. A relative, white bird of paradise (Strelitzia nicolai), is sometimes grown, too. It has a tree-like habit and can easily reach 25 feet tall. It generally doesn't bloom indoors until it's too tall to fit beneath the average ceiling.

If you want fantastic blooms, be sure bird of paradise has a spot with very bright light. Water freely and fertilize in spring and summer with a houseplant fertilizer meant for blooming plants. In winter, water sparingly (enough so the potting mix dries between waterings), and fertilize less than in the summer. Be patient with these plants--they don't produce their first blooms until they are a few years old.

Rex begonia
While the word begonia may bring to mind ordinary, run-of-the-mill houseplants, rex begonias (Begonia rex) are anything but. Many have wildly variegated leaves touched with silver, black, red, green, or purple. For example, ‘Fireworks' has leaves with black-purple centers surrounded by silver and medium-purple leaf edges. The leaves of ‘Persian Swirl' bear the same variegation, except it's in a spiral shape.

A rex begonia likes moderate to bright light and soil that dries between waterings. It is susceptible to problems from over-watering. Give it good humidity to keep leaf edges from turning brown and crispy.