Hibiscus – By Mark Govan, Host “Florida Gardening”

This week I would like to talk about another of my favorite plants, the Hibiscus. Hibiscus has been grown in Florida gardens for many years however the plant originated in the Pacific islands and Malaysia. A lot of people think of Hawaiiwhen they see the colorful blooms and tropical look, this is why you should have at least one of these plants in your landscape. If you have not had the opportunity to grow a hibiscus, then you need to read this article and learn how to grow and care for the standard “single” hibiscus, the newer “Dinner Plate” hibiscus with their large showy flowers, and the “weeping” hibiscus “schizopetalis”. This article will describe these varieties of Hibiscus and I will tell you about some of the problems associated with growing Hibiscus.  

            The Hibiscus is a flowering plant or tree which belongs to the Mallow family. Depending on the variety, flowers of this plant can range in size from three inches across to over a foot. Some flowers retain their color through the bloom cycle while others change color as the flower ages. Although some parts of the plant can be used for medicinal purposes, most homeowners grow this plant for the flowers or the color this plant adds to the garden. Hibiscus flowers have been used for years in decorating the home as cut flowers. In some cultures women also use the flowers by tucking them behind their ear to show availability to marriage. Most cut flowers are used for decoration.

            Hibiscus flowers come in a rainbow of color. The only colors which are not available are a true blue or a true black flower. Do not let this discourage you as new hybrids are constantly being introduced and in the future we may see these colors cultivated. What you can count on now is the sheer multitude of shapes and sizes of these flowers to fit any landscape. Many of the common varieties such as the single reds are very easy to grow and take minimum care. Hibiscus wants to be grown in full sun and if cared for properly will produce an abundance of flowers on the new growth produced each year.

            Hibiscus prefers to be planted in rich soil consisting of peat and perlite. A pH of six to six point five is great for growing a healthy plant. Fertilizer should be added every two months to support the new growth where the blossoms form. Most hibiscuses will produce a small to medium sized shrub of four to six feet in height but others can reach a height of up to twenty feet. Some plants are compact and dense while others may be open and thin. Be sure to select the type of hibiscus which will suit your landscape. Once you select your plant you will need to do some trimming or pruning to maintain the shape you want. Because hibiscus blooms on new growth, you will need to allow the plant to bloom before you shape the plant. I like to allow the plant to attain the height I desire first, then I will do a little pruning from the top to help the lower parts of the plant fill in. Be sure that when you prune your plants that you try to make the top of the plant skinnier than the bottom. If you let the top of the plant become too large you will reduce the light on the lower part of the plant which will reduce the foliage.

            Hibiscus come in various colors and some of the prettiest are the singles. Single flowered hibiscus produce copious amounts of flowers on a single plant and are easy to care for. Red, yellows, or pink flowers open daily during our warm months giving you season long enjoyment of your plant. Standard singles are the easiest to grow and most common in the landscape. Most nurseries’ carry several different colors of hibiscus at any one time giving you choices which sometimes may be hard. Just be sure to pick plants that are of the same cultivar because as they grow in the landscape they will complement each other. Picking out different cultivars of hibiscus can be ok but remember, each cultivars growth habits may be different. If you plan on using hibiscus in a hedge you would probably want to use one color or several colors of the variety Hibiscus “rosa chinensis”. This will help to maintain a balanced look in the garden.

            The “Dinner Plate” hibiscus is noted for their very large flowers and interesting colors. These hibiscuses are normally grafted by the grower on a seedling rootstock and are readily available at many of the local plant shows such as the University of Florida Botanical Garden. Most are available for purchase in one gallon containers. These plants will grow to a size of about three feet or more and are best suited to specialty gardens or areas of the garden which are managed more closely. Some people like to plant them in containers so they can move them around the garden. Because most of these plants are grafted, they need to be protected in cold spells. I have planted several of these varieties in my garden and they are in the southern exposure. I like to protect them from cold air or freezes by using either a frost cloth or if they are in a container I will take them inside when the cold weather is upon us.

            The Hibiscus “schizopetalis” is an open grower. Flowers are formed on long branches and when the flowers mature the branches tend to weep from the weight of the flowers. This particular hibiscus is most often used as a specimen plant in the garden. I never mix this cultivar with other hibiscus as the leaves are smaller and the flowers are different from the standard single hibiscus. Plant these in front of a window or in a corner as this plant will grow to six to eight feet tall and produce many of these attractive blossoms. The flower looks to be inverted as the pistol and stamens actually hang down from the flower which tends to grow upward. 

            There are a few problems that hibiscuses have and this one is very important. There is a new pest which was introduced to Floridaseveral years ago called the Pink Hibiscus Mealy bug or PHM. Most of us are familiar with mealybugs as we have had to control them on many of our plants in the past. Mealybugs (or woolly aphid) are found primarily on succulents, they live on the plant or on the roots in the soil and are very efficient at killing houseplants and even landscape plants.

            Mealybugs look similar to scales found on many plants but can be distinguished by their hairy or waxy otter covering. Another distinguishing characteristic is that these insects move readily from plant to plant eagerly infesting other plant throughout your landscape. Mealybugs reproduce by laying eggs underneath a cotton-like covering which protects the eggs until they hatch. The new PHM is a mealy bug on steroids and is resistant to most current insecticides. PHM’s tend to group at the tips of the branches near the flower bud and cause a distortion of the leaves and in many cases causes the blooms to abort. The only control is either professional application by a certified pest control applicator or the use of a systemic insecticide such as Imidicloprid found in Bayer’s Advance 12 month Tree and Shrub Care. This will also control aphids and other scales which feed on hibiscus.

            Hibiscus can be a wonderful plant in the landscape and I am sure that if you have never used them before, you will now. There are many choices I have outlined for you above so enjoy your garden and remember, without plants we would not be here. 

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