Plants that can beat the heat


Tropical plants thrive in the warm, humid environment of the tropics, and in an Arkansas summer, it often feels somewhat tropical outside. A wide range of tropical plants, both foliage and flowers, can be found at nurseries and garden centers statewide, and there should still be some available. If you looked for them early this season, selection was not as good. Late cold snaps and tropical storms took their toll on some of the nurseries that produce these plants in Florida and other southern climes, but they are making a comeback, and we are beginning to see more on the market.

Tropical blooms can thrive in Arkansas summers.

One of the most common of the tropical flowers is the flowering hibiscus, which comes in a wide range of colors and sizes. All hibiscus plants are in the mallow family. The tropical or Chinese hibiscus, known botanically as Hibiscus rosa-sinensis, is native to tropical Asia. They have leathery, glossy leaves, with some varieties having variegated foliage. Depending on variety, flowers can be single or double, with colors ranging from white, yellow, orange, pink and all shades of red, with single colors or multi-colored blooms. Each flower only lasts one day, but given plenty of sunlight and ample nutrients, these plants can produce enough flower buds to give you flowers all season, provided they get full sun, plenty of moisture and regular feedings.

Mandevilla (also called dipladenia) is a beautiful and highly popular tropical flower. The original mandevilla was a vigorous vine with vibrant pink blooms. Through breeding, we now have a lot more options, including plants with various shades of pink, red, white, yellow and even apricot-colored blooms. The plants can be prolific vining plants, or more compact and bushy. They all thrive in full sun.

Bougainvillea is often sold in hanging baskets and cascades down with showy colorful bracts. The true flower is the tiny white one inside the colorful bracts, which can be pink, red, yellow or orange. They usually do best if given limited root space to grow in. If you give them a large container, they spend too much energy growing foliage and roots, which can limit the flowers. Do be aware that there are small thorns along the stems.

Ixora is an evergreen shrub in tropical climates, but it makes a fantastic flowering container plant that will bloom non-stop all summer. The flowers are in shades of orange, red or yellow. It will do well in a container or planted as a summer annual in the ground. It will not survive our winters outdoors.

Some other less common, but well worth trying, tropical plants include plumeria, the fragrant flower associated with Hawaii; iochroma with clusters of purple or apricot flowers; tibouchina with deep purple velvet blooms; and Rangoon Creeper, a beautiful vining plant with flowers that change from white to deep pink as they age.

While we love the color we can achieve with flowers, there are also some outstanding tropical foliage plants. Bananas, both standard and dwarfs, give you a tropical look, along with palms, colorful crotons and a whole lineup of houseplants. If you move your houseplants outside for the summer, consider placing them among your shrubs and garden plants to add an extra dimension of color and form before moving them back indoors for the fall.

As with houseplants, tropical flowering plants can’t survive outside year-round. Some gardeners choose to buy new plants every year, while others move them indoors.

Hibiscus come in many colors.

Tropical flowering plants bloom on new growth. If the plants aren’t putting on much new growth, they won’t bloom as well. Since most are container-grown, we also water frequently this time of year, which leaches out the nutrition. Depending on the size of the container, daily watering is often needed during the hottest, driest times. Frequency will depend on the size of the container, the size of the plant, how exposed the plant is and the temperature. To keep your plants in constant bloom, fertilize often — every two to three weeks with a water-soluble fertilizer or less frequently with some of the slow-release types. Make sure the plants are well-watered before you fertilize so you don’t burn them.

Pests are not common on tropical flowers, but can include aphids, white fly and spider mites. Monitor for them closely and control as needed. If you do plan to overwinter them indoors this fall, be sure to carefully inspect them prior to bringing them indoors.

If your garden needs some extra color now, choose tropicals. Even if you can’t stand the heat, they can!

Janet B. Carson is an extension horticulture specialist for the University of Arkansas Cooperative Extension Service.