Hibiscus are beautiful plants, bearing large trumpet-like blooms in a range of colours, depending on the species. There are two main types of hibiscus – hardy deciduous hibiscus (Hibiscus syriacus, used in outdoor planting schemes) and tender evergreen hibiscus (Hibiscus rosa-sinensis, which is grown as a house plant). Hardy hibiscus is also called rose of Sharon.
Although the flowers are similar, hardy hibiscus are different from tropical hibiscus in several ways. Native to southern China, hardy hibiscus tolerates our winters, while tropical hibiscus (native to tropical China) needs a minimum temperature of 7ºC to thrive. Hardy hibiscus bars large, single flowers in red, white, lavender and pink. Tropical hibiscus flower in shades of pink, orange and yellow. Hardy hibiscus has heart-shaped, matt leaves while tropical hibiscus has darker green, glossy leaves.
Hardy hibiscus is easy to grow. Tropical (indoor) hibiscus makes a fine house plant, flowering from May to October if happy, but it can be tricky to grow.
How to grow hibiscus
Grow outdoor hibiscus in moist but well-drained soil in a warm and sunny spot, ideally sheltered from winds. They do well in pots of loam-based, peat-free compost.
Grow indoor hibiscus in a bright spot away from direct, strong sunlight. They need a minimum temperature of 7-10°C and a high humidity, so do well in bright, but not sunny, bathrooms.
Both types of hibiscus do well in pots of moist but well-drained soil or compost. Repot in spring every two-three years to keep it fresh.
Where to grow hibiscus
Grow outdoor hibiscus in a sunny, sheltered spot such as a border or container display. Grow indoor hibiscus in a bright, humid spot out of direct sunlight.
How to care for hibiscus
Feed outdoor hibiscus annually in spring, with a slow-release, high potash formula, such as rose food. Mulch in autumn to help maintain soil moisture levels and suppress weeds. Don’t be alarmed if your outdoor hibiscus dies back after a hard frost in autumn – remember they are deciduous and this is perfectly normal. Simply cut back dead stems to around 10cm above ground level. They will regrow the following May to June (again, don’t be alarmed by the late development of leaves, spring growth is slow to appear on outdoor hibiscus).
After three years (or when it’s reached a height of around 1.5m), start pruning your hardy hibiscus annually to keep in shape. If left unpruned, the outer branches can fall outwards from the weight of the leaves.
Prune after flowering, cutting each branch back to a leaf node at a desired height. Removing old wood from the centre of the plant can improve air circulation.
Water indoor hibiscus regularly during the growing season (spring to early autumn) and feed fortnightly with a high potash liquid feed. Cut down on watering from late autumn to spring, when the plant is dormant. Always let the top few centimetres of compost dry out before watering again.
Indoor hibiscus benefit from annual pruning to keep it in shape. In early spring, simply 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 from their base and thin non-flowering shoots removed.
Growing hibiscus: problem-solving
Hardy hibiscus are relatively trouble-free, and will grow well without much interference from you.
Topical hibiscus can suffer from bud drop if humidity levels are too low. Simply mist regularly or move to a more humid environment such as a bathroom. Wilting is caused by lack of water, if your tropical hibiscus wilts often then repot it into a larger pot.
Keep an eye out for red spider mite on tropical hibiscus, which thrive in dry environments. Increase humidity levels to control it.
Advice on buying hibiscus
- Make sure you’re buying the right hibiscus for your home or garden. Remember that Hibiscus syriacus is the hardy, outdoor hibiscus, and Hibiscus rosa-sinensis is the tropical, indoor hibiscus
- Choose plants with no signs of disease or pests, with healthy leaves and buds
- Some hibiscus will be available at garden centres but you’ll find a wider choice at online retailers.
Where to buy hibiscus