Question: A hibiscus plant is one of the plants we brought back from our Hawaiian vacation. Can Hibiscus be grown indoors? We also saw small hibiscus trees that were interesting but like the bush type much better. Can hibiscus be grown outdoors in a pot on a patio or deck? Courtney, Nashville, Tennessee
Answer: Hawaii and Hibiscus – picturesque words bringing to mind a vision of sunny skies and hula dancers adorning their dark tresses, exotic blossoms and tropical climate.
At one time the famous “Hawaiian lei” was made only of green material until the brilliance of hibiscus bloom impelled the bronze-skinned maids to add color to these tokens of friendship.
The hibiscus (hy-BIS-kus) lends itself beautifully to pot culture, and because there is no dormant season for the potted plant, it may be kept in bloom the year around.
It ranks high in popularity along the Gulf Coast in Florida and Texas and in Southern California as well as a colorful spring time plant for the northern patio.
In fact, George Washington ordered hibiscus from Philadelphia nurseryman John Bartram in 1792. These plants had single, red flowers, similar to the present day variety.
Easy Care Hibiscus – Colorful Results
Given sun, moisture, good drainage and a temperature which stays above 32 degrees the year round, hibiscus will reward the grower with blossoms almost continuously but most prolifically during the summer and fall months.
Even in the north the gardener need not be without them, for they make fine large pot plants for a sunny window and may be placed outdoors on the patio in the summer.
Plants may set too many buds for the root development to support and some or all of the buds will fall for a time. Fertilizing and additional humus will usually take care of this.
Lots of Sunshine
Plenty of sunshine is necessary to make the plant grow sturdy and to produce blooms. To insure good branching, the plants should be pinched when small.
If the pinching is done just above an outside bud, the new growth will branch out into a desirable bush.
The flowers are borne on the young wood, and a heavy pruning is in order every year so that plenty of new growth can develop without the bush becoming too large for indoor growing.
Hibiscus thrive under fluorescent light culture. The tubes are placed so that they do not quite touch the top foliage of the plant.
Hibiscus matensis, a species with variegated pink, silver and green leaves, has been known to thrive and flower all winter under fluorescent lights. The fluorescent unit can be made of two 48-watt tubes. Given much humidity and 12 to 15 hours daily illumination, they all do well under the lights.
Growing temperatures should range from 60 to 65 at night to 75 during the daytime.
A bushy plant, three feet tall, will thrive in a six to eight inch pot.
Hibiscus is not particular about soil. It will combat root rot and nematodes best if plenty of humus is added and a neutral pH is maintained.
Soil with perfect drainage and a rich and humusy growing medium will yield rich results. Soil that grows good African violets is usually satisfactory for hibiscus.
Here is a recipe for hibiscus potting soil: equal parts garden loam, peat moss, fine bark and sand.
Hibiscus use large amounts of water, and watering may be required every day. This free use of water leaches out the food in the soil quickly. When using liquid food, fertilizing is necessary every week.
A plant food that has too much nitrogen will give too much foliage and not enough flowers – a well-balanced food should give blossoms that are well colored, quite large, and in normal quantity.
Hibiscus Propagation – Making Cuttings
Although the shrub first came from eastern Asia it has proved its adaptability in subtropical areas where gardeners are enthusiastically searching for new types to add to known varieties.
Hibiscus are easily propagated by using soft wood cuttings or leaf bud cuttings from March to September. Hard wood cuttings may be used almost anytime of year. Hibiscus can also be propagated and grown from air-layers.
A rooting medium of sand or perlite and peat-moss may be used and the cuttings treated with hormones. Or, if the grower is a green thumber, the 6 to 8-inch lengths of stem with two or three leaves or half leaves at the top may be put into a bed which will be kept moist and, presto, they’ll grow and bloom.
The rooted cuttings then may be potted until they are transferred to larger containers or to permanent beds.
They will root in water, or they may be started in a moist mixture of peat moss and sand, or in vermiculite. When roots form, they should be potted into regular soil. Cuttings rooted under fluorescent lights can be potted in six weeks’ time, and flowered in less than a year.
Grafting is done to secure blooms from rare varieties on older rootstock more vigorous than its own. If grafting fascinates you, five or six varieties of hibiscus may be grafted onto one root stock.
The seeds are large enough to be easily handled, and blossoms come in about 18 months. Seeds can be planted in vermiculite, peat moss, or sand – best of all, a mixture of the three.
It is wise to supply an individual pot for each seed. This saves transplanting shock later on. To set seeds on a plant, simply place loose pollen from one bloom into the little pads of stigma at the top of the pistular column of another bloom.
All varieties are not fertile, but a little experimenting will teach which ones will set seed.
When temperatures dip to the 30′s hibiscus may be frozen to the ground. In such cases it may recover slowly or not at all.
But the plants may be covered and protected. Sudden changes in temperature are not easy to meet because warm days are interrupted by chilling, blustery north winds called “northers.”
Hibiscus thrive outdoors in the summer. When you put it out in May or June, thin out weak wood and prune to make the bush as shapely as possible. Keep the plant in partial shade.
Landscape, Hedge and Foundation Plantings
Used as a hedge Hibiscus may be kept trimmed for semi-formal hedges but few blooms are produced. Clumps of hibiscus are most attractive.
The hibiscus is not well suited for foundation planting, especially if the landscaping plan calls for formal or semi-formal types. Along the sides or at the back of the house this may be used where a tall plant is needed.
Hibiscus make fine specimen plants. When they are used in this way near the house, most growers cut them to two feet or less in height late each fall or cut back the older wood to the ground.
If this is not done many types grow too large for the average house. Pruning back the older wood does not decrease bloom, for hibiscus flowers on new wood.
Since there are no standardized names for hibiscus varieties, especially in the newer hybrids, a name may prevail in one section for a red which is applied to a yellow in another section. The safest method, unless blooming plants can be seen in a nursery, is to beg a cutting from a friend, who has a wanted variety.
Flowers Alone Deliver Garden Color Interest Indoors
These brilliant plants add color interest to the garden and are equally useful as cut flowers.
Blooms can be gathered without foliage to use in a cluster on a mirror or tray, or to string along some willowy bamboo straws or palm ribs to add tropical charm to daytime decorations.
The buds may be cut early, on the morning they are to open, and placed in the refrigerator until a few hours before they are to be used. Brought into the light they will open and hold their beauty for almost the twelve hours nature intended for them.
By this method they are tricked into evening use. They give a wide choice in color from white through delicate pinks, yellows, peach and lavender tints, to the most brilliant red and orange shades.
In Mexico these and other hibiscus or mallows are called Tulipan. Down in southern Texas, Hibiscus syriacus is known as althea, Hibiscus palustris (moscheutos) is mallow, rose mallow or Mexican hibiscus and Hibiscus mutabilis is Confederate rose or flower-for-a-day. The hibiscus is the only one called by its genus name.
The hibiscus is known as shoe-black plant in China because of the use made of a dye from the petals. The botanical name, Hibiscus rosa-sinensis, or rose of China elevates it above this association with us.
Vibrant and Colorful Hibiscus
I do not think I have ever seen a hibiscus with a flower that was not colorful and vibrant. You can select from reds, maroon to rosy red, pinks, lavender and white shades along with orange tones.
Each grower who specializes in hibiscus can add names to the list and each collector will continue to admire new hues and search for new types. “Hibiscus-mania” is developing rapidly and growers are not always able to supply the demand for newer types.
Other hibiscus are grown in the south but they die to the ground in the winter or loose their leaves. Hibiscus is evergreen there in normal years.
Northern gardeners who grow these shrubs in pots move them inside during the winter. Pot and tubgrown plants cannot develop to outdoor size and beauty except under specialized conditions.
The hibiscus will continue to be a shrub for the extreme south and an increasingly popular one.
It is said that the flowers can be rubbed on the shoes in place of blacking when one needs a shine. The hibiscus is of the shoe-flower family, and is closely related to hollyhocks, the rose of Sharon, okra and cotton.
The flowers in the wild afford a red dye that is commonly used in cookery coloring.
If you order a plant that comes in a small pot and the leaves are rather banged and bruised, cut the top back partially to give the roots a momentary rest and then a chance to grow.
A plant without a good root system cannot be expected to continue to produce a floriferous plant.
Pests Not Many
Hibiscus pests are not many – aphids, red spiders and mealybugs are about the worst that attack.
Aphids can be licked with a natural pest repellent or one of the house plant sprays; red spiders detest high humidity which hibiscus need to thrive, and mealy-bugs can be wiped out with a spray, or by dabbing them with alcohol. Weekly spraying with tepid water keeps the foliage clean and attractive.
Dropping Buds or Blooms?
Question: Why do the flower buds and leaves of my Chinese hibiscus turn yellow and drop off before blooming time? RR, CA
Answer: Perhaps there is something wrong with the location of your hibiscus. It should have good light and a well-drained soil.