Hibiscus

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Indoor Plants

Onglets

Botany

Origin and description

We find this shrub, which can reach three to five meters in height, in different tropical regions of Asia. It is grown for its 10-15 cm solitary red flowers. Although they fade quickly, the plant blooms all summer long. Hibiscus rarely exceed a height of 1.5 meters indoors. There are many cultivars with single or double flowers of different colors and foliage of various shapes.

Species, cultivars and related plants

There are many cultivars with single or double flowers of different colors (red, yellow, orange, white or bicolor). Leaves, usually dark green and toothed, can take many forms (from oval to highly lobed), depending on the cultivar. Hibiscus rosa-sinensis ‘Cooperi’ has green variegated foliage, tinged with pink and cream, and scarlet flowers.

Common name

Hibiscus / Chinese hibiscus / China rose

Latin name (genus)

Hibiscus rosa-sinensis

English common name

Hibiscus / Chinese hibiscus / China rose

French common name

Hibiscus / Hibiscus rose de Chine / Ketmie

Botanical family

Malvaceae

Horticulture

Growing conditions

Hibiscus requires a lot of light and sun. Place the plant near a sunny window, preferably facing west or south. A temperature of about 20 to 22ºC during the growth period and around 18 to 20ºC in winter is ideal – it should never fall below 15ºC. Also avoid sudden changes in temperature, cold drafts and heat sources. Hibiscus tolerates a dry atmosphere but prefers it when the air humidity is high. This plant is often grown outdoors in summer. Acclimatize gradually, placing it in light shade protected from prevailing winds for two weeks before putting it in full sun. Bring it back inside at the beginning of September, before the first frost.

Easy to grow?

Hibiscus is quite easy to grow as long as there is enough light, but inadequate watering or air humidity can often cause yellowing and leaf drop. It is a plant that grows vigorously, but flowering is regular and frequent only if growing conditions are adequate.

Watering and fertilizer

In summer, water regularly, letting the soil surface dry slightly between waterings. Outside, water more frequently, as the soil will dry more quickly. In winter, reduce watering frequency and let the soil dry a little more, especially if the temperature is cooler. During the growing season (March to October), fertilize once a month with a flowering plant fertilizer rich in phosphorus, such as 15-30-15, or with a balanced fertilizer like 20-20-20. Stop fertilizing in the winter.

Pruning and maintenance

For abundant summer flowering, prune severely and regularly, pinching the ends of the stems in spring, as flowers will form on new growth during the summer. If necessary, remove stems that are weak, too long or dried out. To rejuvenate or contain the growth of a hibiscus, prune the stems and roots in equal proportions in the spring before re-potting.

Repotting

The hibiscus will stop flowering if it is too cramped in its pot, so choose a slightly larger pot where the roots can spread. Transplant preferably in the spring, in tropical plant potting mixture that is rich in organic matter and drains well.

Propagation

By stem cutting and woody cuttings.

Aphids

There are thousands of species of aphids in the world. These tiny, highly prolific insects feed by sucking the sap from a wide range of ornamental and food plants. They form dense colonies on young shoots and under leaves, and also feed on plant stems, bark, roots and fruit.
Scales (Indoor)

The scale insect superfamily (Coccoidea) includes several genera of sucking insects capable of damaging indoor plants. Most of them are tropical, non-hardy species, but they adapt very well to our homes.
Thrips

Over 5,000 species of thrips have been identified around the globe, hundreds of them in North America. Western flower thrips (Frankliniella occidentalis) and onion thrips (Thrips tabaci) are the greenhouse species that cause the most damage in Quebec.
Two-Spotted Spider Mite

Two-spotted spider mites are not true insects, but tiny arthropods, just like other mites and ticks. With their four pairs of legs, they look like miniature spiders. They are so small that they are difficult to see, but they do weave tell-tale whitish webbing.
Whitefly

Whiteflies are major greenhouse and houseplant pests.

Physiological disorders

Symptoms	Possible causes	Solutions
Curling leaves	Air too dry	Increase air humidity
Drop of flower buds and leaves	Inadequate growing conditions: Too much or too little water Air too dry Temperature too cold and/or drafts Lack of light Rapid change of growing conditions (especially light)	Water as needed, letting surface soil dry between waterings Maintain high air humidity, spray foliage Increase room temperature and protect from drafts Place plant in a sunnier room Acclimatize the plant gradually to new environments
Lack of flowering	Lack of light	Place plant in a sunnier location and if possible move it outdoors for the summer
Intermittent or sparse flowering	Temperature variations or lack of light Improper pruning Lack of fertilizer	Stabilize temperature, especially in winter, when there is insufficient light to stimulate flowering Prune in the spring Adjust fertilization

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