How To Grow Exotic Hibiscus

Bring a touch of the tropics to your house or garden

If you want a touch of the tropics then Hibiscus are ideal; either for the house or the garden. There are several hundred species being native to the tropics, sub-tropics and warm-temperate regions. Flower size ranges from 4 – 30cm (1.5 – 12”). It is a member of the mallow family. In the UK indoor varieties are evergreen whilst outdoor varieties are deciduous. Flowers usually only last for a day but are readily replaced. The flowers can be single or double and come in quite an extensive colour range: blue, pink, red, purple, white, yellow and orange. In the garden they are attractive to butterflies.

The flowers are edible having a tart, citrus taste. They are used to flavour dishes, as a tea and candied for decorative use. They are mildly diuretic and contain minerals and vitamin C. There have been studies which suggest they may be used to lower blood pressure.

Hibiscus as a houseplant

These are usually Hibiscus rosa-sinensis, commonly called the ‘Rose of China’. They are an evergreen sub-tropical species reaching a height of 2.5 – 5m (8 – 15’) and a spread of 1.5 – 3m (5 – 10’) in the wild. They need a minimum temperature of 10C (50F) and a position in full sun; they can tolerate light shade in the heat of the midday sun. Make sure the compost is kept damp but not sodden and don’t let them stand in a tray of water. Use a free draining humus rich compost. Re-pot when the roots have filled the pot; to just one size larger. Cease feeding and reduce watering in winter. If the plant has been outside in the summer bringing it back indoors may cause the leaves to drop but reducing watering should remedy this; but care should be taken not to let it dry out. Bud drop can be a problem which can be caused by being too hot, 29C (85F) or too cold, 7C (45F); once temperatures reach an acceptable level the problem should cease. Bud drop can also be caused by over or under watering.

Hibiscus syriacus 'Blue Chiffon'

Hibiscus syriacus 'Blue Chiffon'

Hibiscus as a garden plant

This variety is Hibiscus syriacus originating from the Far East. It needs an open, sunny, sheltered site as it is only hardy down to -8C (18F). Thick mulch will help it withstand a cold winter. The soil needs to be humus rich and well drained as it needs to be kept damp but not wet. It needs a high potash feed, such as Tomorite, twice a month during the flowering period as this promotes flowers. An annual dose of rose fertiliser would also be beneficial. It can be pruned hard in spring as it flowers on this years growth. It should flower about 3 – 4 months after pruning. They can be slow to leaf up in spring so give it a chance before condemning it to the compost heap. They can be attacked by pests such as aphids and mealybugs so at the first sighting spray with a systemic insecticide or an organic contact spray.