Tropical Hibiscus

Growing Tropical Hibiscus

A popular plant sold at box stores and nurseries is the Tropical Hibiscus (Hibiscus rosa- sinensis). This well-known species is hardy along the Gulf Coast, California, Florida and Hawaii but can be set outdoors for the summer in any part of the country. There are hundreds of cultivars that come in various shaped flowers as well as in almost every color and are sold as container plants in bush or topiary form.

Hibiscus need, well-drained slightly acid soil, direct sun and some protection (filtered shade) when temperatures are in the 90 degrees. When you bring it out for the first time you need to acclimate it to the intense heat and sun. They also like a lot of water. Fertilize lightly and often with a diluted 10-10-10 or 20-20-20 during the active growing season.

The disk like flowers will usually last a day or two and come in single five petals, crested single, double and cup saucer double. Hibiscus has active periods of bloom that are followed by a rest, indoors and out. So if your plant stopped blooming for a while, it may be just resting.

Over wintering
In cooler climates, hibiscus can be enjoyed as a houseplants. When the night temperatures drop below 50F degrees bring your hibiscus indoors for the winter. To help endure the long season, keep it in a (65-75), bright sunny room (4-5 hrs) away from direct heat and drafts. Water less but keep the soil evenly moist and provide humidity with a humidifier or a pebble tray filled with water. Check for pests such as aphids, whitefly and spider mites and treat with insecticidal soap if infestation occurs.
Another option is to let your hibiscus become dormant for the winter. Bring it indoors and stop watering until soil is dry and the leaves have fallen off. Then place it in a cool, dark room with temperatures of 40-45F. Check the soil periodically to make sure it doesn’t totally dry out. When the top 2-3 inches are dry, water just enough to moisten the soil and keep the plant from dying .
In the spring, move your hibiscus outdoors when night temperatures are above 50F.
With a little care you can enjoy these tropical flowers all year long.

If your plant has grown leggy and out of control you can prune it 1/3-1/2 in early spring to reshape and keep it bushy. Pruning the roots in the fall also helps slow down branch growth.

Yellow leaves & leaf drop
A common occurrence is yellowing leaves and leaf drop; which can be caused by overwatering or underwatering. How do you determine which one? Look at the root ball. Is it potbound? Meaning are the roots so tight that they are growing in a circular pattern with little soil left? Do water everyday and the plant still looks dry? If this is happening chances are you are ‘underwatering’. There is not enough soil to retain any water and nutrients. Instead of soaking in, the water and nutrients are flowing right through the drain holes leaving your plant thirsty and hungry. It’s time to repot into a larger container. The best time to repot is in the spring but if that can’t wait add more soil to your container to help with water absorption.