Exotic, intriguing and beautiful are only a few of the many descriptions of
tropical hibiscus, Hibiscus rosasinensis. They make a grand statement in any collection of indoor plants and are among the best blooming plants for the summer patio. The large, showy Hibiscus blooms are deep-throated and look like they are made of crepe paper. Each fat bud opens into a bloom that is several inches across. Luckily, buds develop rapidly and are opening constantly, because each flower only lasts a day or two before fading. Native to southern China, these tropical plants are also called Chinese hibiscus and are commonly grown as both bushes and trees. Tropical hibiscus are capable of living for years and years and outgrowing even the largest of homes. In Minnesota, with our long, dark winters, they are more commonly kept for the outdoor growing season or as an indoor plant for a few months. There are thousands of varieties of this versatile plant offering a wide selection of colors, often with a contrasting color in the throat of each bloom or a blush of another color along the edges of the petals. Tropical Hibiscus blooms can be either single or double. The foliage varies slightly in different varieties, but on the whole, Hibiscus have rather large, dark-green, glossy leaves. Tropical hibiscus are not hardy in our area and resent temperatures below 50º. There are other types of hibiscus that do grow in Minnesota, such as the Dixie and Disco Belle series of the Southern Belle Hibiscus, H. moscheutos and Lord Baltimore, H. coccineus. While these varieties are hardier than the tropical hibiscus, theyare sold as herbaceous perennials in our climate where they typically die back to the ground each winter.

Tips for Growing Healthy Tropical Hibiscus
What are the light requirements for hibiscus? They need lots of light. After they have been acclimated (slowly accustomed to it) they will do best with full sun.

How much water do they need? As soon the soil begins to dry, thoroughly drench the root mass. Keeping the soil evenly moist is important during the summer when they are blooming and exposed to drying breezes. During cooler weather and when they are indoors, let them get a little dry before watering.

Do they have any special temperature requirements? They are very sensitive to temperatures below 50º and thrive in temperatures from 60-85º. When it is hotter, be sure to increase the humidity and water.

Do hibiscus need much humidity? They enjoy being sprayed frequently if the water isn't too cold. To raise the humidity, use a humidifier or keep the plant on pebble tray.

How much fertilizer do they require? Hibiscus are heavy feeders when they are actively growing and blooming. Feed them every other week during spring and summer with an all-purpose, water soluble fertilizer such as Bachman's Excel Gro™. During fall and winter, cut back to once a month. If your water is very alkaline (like most city water in our area), add 1 tablespoon vinegar to each gallon of water used for your hibiscus to keep the soil pH closer to the 6.5 hibiscus prefer.

What type of soil do they prefer? Hibiscus grow best in a well-drained quality potting soil such as Exceloam.

When should I repot my hibiscus? They bloom best when they are slightly crowded in the pot. Check in the spring. If your plant is too crowded, repot it into a container no more than 2 inches larger. If it is already in a fairly large container (14 inches or more), consider replacing the top 2” of soil instead of increasing the pot size.

Will they need any grooming? As blooms fade, remove the stem that held the bloom. Prune in mid- to late winter. If you prune later, you may delay blooming.

How are they propagated? Tropical hibiscus are usually propagated by rooting stem cuttings, but it isn't easy. Take lots of cuttings and hope for a few to root. Hibiscus can be grown from seed, but it may take a year or more to get the plant to blooming size.

Troubleshooting Problems with Tropical Hibiscus
What causes the leaves to yellow and drop? This is a real problem with hibiscus. They are sensitive to sudden changes and to any temperatures below 50º. With our unpredictable weather, that can cause problems. When the leaves yellow rapidly and drop and the affected leaves are all over the plant, it is almost always from a sudden change and new leaves will quickly replace the old. If the yellowing is confined to the inner sections, check to make sure it is not being over-watered.

Why do buds form and then fall without opening? The most common cause of bud drop is low humidity.

What will make green leaves fall? Make sure the plant isn't being over-watered or nibbled on by some critter.

When the plant looks wilted but has plenty of water, what is the problem? Wilting is a sign of both too much and too little water. It can also result from excessively warm temperatures, especially if the humidity is low. When it gets above 80º, mist the plant often and keep it well watered.

What caused the black spots on the leaves? Hibiscus are sensitive to some leafshine products and the leaves may develop black areas. If the black is specific small spots, see if it will wipe off. If it does, it is probably sooty mold growing on the honeydew dripping from insects on upper branches.

Why would all the leaves look pale? This can be lack of adequate fertilizer or too little light.

What causes the white patches on the leaves? When a plant is exposed suddenly to a lot more sun than it is used to, it develops sunburned patches that are pale gray or white.

Why do some plants grow so tall and straggly? The plant probably needs pruning and stronger light.

Are there insect problems common to hibiscus? Yes. Hibiscus are prone to aphids and whiteflies as well as the occasional spider mite infestation when it is hot and dry. They occasionally get mealy bug too. Use a mild insecticide and repeat applications according to directions.

Are there any disease problems? Other than root rot from prolonged over-watering, they aren't disease prone.

Recommended Products
Quality Hibiscus, Tree and Bush Form
Bachman's Exceloam Potting Soil
Containers and Saucers
Safe and Effective Insecticides
Artificial Lights for Indoor Gardening
Excel Gro™ Water Soluble Fertilizer

©Bachman's 2008