Hibiscus plants are blooming profusely all over Marco right now. This plant seems to love the cold weather. Perhaps it is because the severe cold helps control some of the insects that constantly cause the blossoms to drop. Whatever the reason enjoy the beauty of these glorious flowers.
Hibiscus is believed to be native to China and were seen in the South Pacific and Hawaii before showing up in Florida.
Most varieties have flowers that last one day. The blossoms open early in the morning and are gone by afternoon. Some varieties have flowers that remain open for two days. Although the individual flowers do not last long, the flowering season is nearly all year in South Florida.
People select a hibiscus variety (of which there are many) on the basis of plant growth and size or the form and color of the flowers. Plants range from low, spreading forms to upright varieties reaching twenty feet in height. Some are compact and dense while others are open and thin.
There are tremendous flower variations amongst varieties. There is a broad range of color combinations, color shades and flower forms. Hibiscus flowers are basically characterized as single or double forms with variations in the number and arrangements of petals.
Picked flowers do not have to be placed in water but should be kept in a cool place. The flowers may be saved for evening use if picked just after they have opened in the morning and refrigerated until needed.
Hibiscus is used in the landscape as informal hedges or screens, foundation plants or as background for other plants. They do not perform well as formal sheared hedges. Groupings of similar plants are usually more effective than mixing several varieties due to different growth habits. Most varieties can also be trained to grow with a single trunk and are called “standards”.
Plants can be killed to the ground by 28 – 30 degree F temperatures, but established plants may come out in the spring and bloom on new growth that summer. Hibiscus should be protected from cold northern winds using fences, buildings, trees, etc. They do not tolerate salt spray or saline irrigation water.
Generally, half a day of direct sunlight is the minimum requirement. Hibiscus plants do not tolerate saturated soils or “wet feet”. However, they do require adequate water and will need regular irrigation during periods of drought. About once a week. Also, never plant a hibiscus in a location with an old root system that is still decaying. This can cause disease.
Regular fertilization is essential for healthy vigorous plants. Hibiscus bloom best when fertilized lightly and often, three or four applications a year. An ample supply of micro-nutrients is essential. There are commercial mixtures containing the necessary micro-nutrients making it very convenient for the homeowner to properly fertilize.
Heavy pruning is best done in the early spring and should not be done in late fall or in the winter. Light maintenance pruning may be done any time of the year. Blooming is delayed and reduced if the plants are pruned heavily during the active growing season because blooms are produced on new growth. By cutting the longest, one-third of the branches each month you avoid the need for heavy pruning.
Many pests can feed on hibiscus making this a very high maintenance choice for your landscape. Chewing insects include caterpillars, grasshoppers, snails and slugs, beetles, cut worms & leaf miners. Piercing-sucking insects include scale, mealybugs, spider mites, aphids, whiteflies and thrips. These pests are more of a problem in areas of poor circulation. The grenade scale can be hard to see because it blends with the bark. This soft scale will cause branches to die back. Premature, flower bud-drop has become a more serious problem with hibiscus in part due to the gall midge.
I will go into more detail on the problems of hibiscus and discuss solutions next week.