Hibiscus Are In Bloom!

by Judy Kautz, OSU Extension Master Gardener

Are your hibiscus blooming?  They are beginning to show their glorious color in our neighborhoods?  Everyone loves the large, flamboyant blooms of the hibiscus plant, which add bright color to any yard.  There are two types of hibiscus that we enjoy in Oklahoma:  tropical hibiscus and hardy hibiscus, and both grow well in Oklahoma as shrubs or potted plants in a sunny spot in your garden.

Often referred to as rose mallow, the hardy hibiscus is unlike any other flower in the garden, offering blooms that are both delicate and huge.  Flowers range from 3 - 4 inches across to a gigantic 12 inches in diameter. Hardy hibiscus plants are grown as woody shrubs and can grow up to five feet tall and three feet wide.  They are hardy down to -30 degrees F, and prefer full sun and fertile, well-drained soil.  The foliage of the plant is very attractive, with heart-shaped leaves.  Most hibiscus shrubs tend to leaf out late in the spring, and they will hold their green colored leaves late into the fall.

​Hardy hibiscus come in a variety of colors, varying from red, white, lavender, purple, pink, and magenta.  They leaf out very late in spring, so don't think they're dead and chop them down. Be patient, and in a few weeks you'll have attractive foliage (often finely cut, and sometimes copper colored) and soon a summer full of spectacular blooms.  They begin blooming in mid-summer and will often continue to produce flowers until fall.  Many hardy hibiscus blooms grow to the size of dinner plates!  They definitely add stunning drama and color to any landscape.

Hardy hibiscus blooms comes in many stunning colors.

​There are several plants that are beautiful companions to hardy hibiscus in your garden.  Tickseed, or coreopsis, are slightly smaller than hibiscus and bloom in yellow shades which are very complimentary.  Try a mixture of other easy-to-grow companion plants, such as Shasta daisies, daylilies, delphinium, allium, poppies, peonies and bearded iris. They all grow well in the same soil conditions, light and water requirements as the hardy hibiscus.  For a great example of the combination of hibiscus and Shasta daisies, visit the Cleveland County Master Gardeners Demonstration Gardens, located west of the gravel parking lot at the Cleveland County Fairgrounds.  These beauties are in Bed 2, Easy Perennials.

The hardy hibiscus bloom is stunning when planted with Shasta daisies, and blooms can reach the size of dinner plates.

​Tropical hibiscus should be grown in a container or planter in our area, as they will not survive our cold winters.  They will winter over in your garage or house, so long as they are protected from freezing temperatures.  Their foliage resembles the hydrangea, with long graceful leaves; they also come in a variety of colors, ranging from white, red, yellow, pink, and orange.  They, too, prefer full sun, but can tolerate some shade, as long as they get at least 6 hours of sun a day.

Tropical hibiscus blooms are generally smaller than hardy hibiscus, and often come with double petals like “Apricot Brandy” pictured here.

Maintenance of hibiscus is not complicated.  Pruning plants is a common way to keep your plants compact, but it isn’t necessary.  Do not fertilize your hardy hibiscus after June, as flower production may suffer from the excess nitrogen in the fertilizer; however, tropical hibiscus should be fertilized frequently, since their pots do not retain nutrients.  For hardy hibiscus, winter mulching is not necessary, and they are not usually bothered by pests.  However, tropical hibiscus are susceptible to a variety of insect pests including aphids, scale, mealybugs, thrips and mites, but most plants are resilient enough to withstand pests and continue to thrive and grow.  Also, there are many products such as insecticidal soap available in your local garden center to treat these pests.
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Hibiscus plants are a magnet for hummingbirds and butterflies, and provide a vital source of nectar for these creatures.  Bees also love the hibiscus, and attracting bees to your yard will help to pollinate your other plants.  Add hibiscus to your yard this year for a colorful and beneficial addition to your garden.