Temperatures are heating up, and that is just what some plants like. Hibiscus are great plants for the summer garden in Arkansas heat.
When hearing the word hibiscus, most people imagine the showy, tropical blooming plant Hibiscus rosa-sinensis, but there are others as well. Hibiscus plants are in the mallow family, along with almost 300 species of annuals, perennials, shrubs and even trees. The most common varieties of hibiscus for Arkansas gardens are: the summer-flowering Hibiscus rosa-sinensis; perennial hardy hibiscus, also known as Hibiscus moscheutos and H. coccineus; and the fall-flowering Confederate rose, Hibiscus mutabilis.
In Arkansas, the tropical flowering plant is commonly available in various sizes and a wide range of flower colors. Flowers may be single or double, with one color or two. The flowers on tropical hibiscus only last a day, or sometimes two, but with full sunlight, warm temperatures and ample moisture and fertility, they can bloom nonstop from now through frost. Some gardeners treat them like summer annuals, buying new plants each year, while others move them indoors or into a greenhouse for the winter months. If you keep your plants from year to year, be sure to repot them and prune them back by one-third to one-half before moving them outdoors. Pot-bound plants or large, woody plants won’t produce much new growth, and tropical hibiscus plants bloom on new growth. Actively growing plants have more blooms. Fertilize them every 10 days to two weeks throughout the growing season. Err on the side of light applications, so you don’t burn the foliage.
Perennial hibiscus are related to one of four native hibiscus, commonly called swamp mallow or rose
mallow. The two most common in the trade are: Hibiscus moscheutos, with large heart-shaped leaves and dinner plate-sized blooms in white, pink or red; and the cut-leafed variety with showy scarlet red flowers, Hibiscus coccineus (commonly called Texas Red Star or Scarlet rose mallow). These perennial forms die completely to the ground after a killing frost, then emerge slowly in the spring once the soil has warmed. They love full sun and moist conditions; they are not the most drought-tolerant flower in our garden. In their native habitats, these hibiscus are found in marshy, wet areas.
These perennial hibiscus typically start blooming in June and will bloom for two months or more. The blooms only stay open one day each, but they are show-stopping in size and color. With plant breeding, many new cultivars are available. The mature plants form fairly woody stalks and can range in height from 2 feet to 10 feet or more depending on the variety. Know something about the variety you are purchasing, as some can not only grow tall, but will spread each season as well, especially in moist conditions.
A rose by another name … and changing colors
Hibiscus mutabilis, or the Confederate rose, is another perennial plant, but not reliably winter-hardy in the
northern tier of our state. The common name Confederate rose may make you think they are native to the South, but they are actually native to China. Similar to the other perennial hibiscus, these plants die to the ground in the winter, and they only bloom in the fall. The plants emerge in late spring and grow all summer, gaining heights of 8 to 12 feet or more in one season. Then, in late September or early October, the flowers begin to open. There are several varieties out there, with single or double flowers that open in white or shades of pink.
The name mutabilis was given because each bloom mutates, or changes color, during the course of two to
three days. Some open white and change to dark pink, while others go from light pink to dark pink. When they are in bloom, you will have multiple-colored flowers all over the plant. It can be a stunning accent plant for the fall garden. Not typically sold at nurseries, it is a common pass-along plant shared by gardeners, or sold at Master Gardener plant sales. If you live in an area where they are not winter-hardy, cut some of the woody stalks before a killing frost, and root them during the winter in soil, sand or water. Then move the rooted cuttings outside in the spring after the chance of frost is over.
Occasionally you will find the red-leaf hibiscus, Hibiscus acetosella, which can look like an annual red-leafed Japanese maple. The deep red, maple-like leaves are produced on a bushy shrub-like plant, up to 4 to 5 feet tall and wide in a season. While they can produce dark red flowers, they sometimes get into a growing mode and put on foliage with few blooms. These are tropical plants that would not survive outdoors in an Arkansas winter.
If you are looking for dazzling summer color for the garden, consider hibiscus.