Hibiscus (Hibiscus)

Hibiscus (Hibiscus)

Hibiscus are very showy plants, producing large trumpet-like flowers in a wide range of colours, depending on the variety grown.

Although there are dozens of species, there are two main types - hardy outdoor deciduous shrubs (mainly varieties of Hibiscus syriacus) and indoor evergreen plants (mainly varieties of Hibiscus rosa-sinensis).

Indoor varieties of hibiscus have a long flowering period - from around May to October - but they can be a bit tricky to keep growing and flowering from year to year, if not given the right conditions.

The hardy, outdoor varieties are much easier to look after and, providing they get plenty of light, will produce fabulous floral displays for many years.


How to grow hibiscus

Cultivation

Outside

Hibiscus needs a warm position in full sun, preferably sheltered from strong and cold winds. It prefers a well-drained soil that remains moist during summer.

Hibiscus are perfect for growing in large containers of John Innes No 3 compost in a warm and sunny position.

Inside

Indoor hibiscus need a position in good, bright light but protected from direct, strong sunlight in summer. They prefer a humid atmosphere and need a minimum temperature of 7-10°C (45-50°F).

They are not too fussy about compost, any good potting compost that drains freely is suitable, although one with John Innes would be preferable. They will need re-potting every couple of years - preferably in March or April.

Plants can be moved outdoors in summer to a position protected from direct sunlight, but must be brought back indoors in autumn before temperatures reach 10°C (50°F).

Hibiscus flowers closeup

Suggested planting locations and garden types

Flower borders and beds, patios, containers, city and courtyard gardens, screening, houseplant, indoor plant, summer patio plant.


How to care for hibiscus

Outside

In spring, give them a good feed with preferably a high potash granular feed, such as a rose food.

Mulching the soil will help to maintain soil moisture levels and keep down weed growth.

Outdoor hibiscus don’t need regular or routine pruning. In February/March, prune out any dying, diseased or damaged stems, plus any excessively congested or crossing stems and any that are growing in the wrong or unwanted direction.

Inside

Water regularly when plants are in growth (April to September), but more sparingly when dormant (autumn and winter). Allow the top of the compost to slightly dry out before watering again.

Feed with a high potash liquid feed every 10-14 days during the growing season, from spring to early autumn, especially when in flower.

You can keep plant compact, bushy and flowering well with annual pruning. In February/March, shorten the previous year’s growth to produce a main framework of branches, which will then produce flowering shoots. Unwanted long shoots can be pruned back to 5-7.5cm (2-3in) from their base and thin non-flowering shoots removed.

Flowering season(s) Summer, Autumn
Foliage season(s) Spring, Summer, Autumn, Winter
Sunlight Full sun
Soil type Chalky, Clay, Loamy, Sandy
Soil pH Neutral
Soil moisture Moist but well-drained
Ultimate height 1.5-1.8m (5-6ft)
Ultimate spread 1.2m (4ft)
Time to ultimate height 6-10 years