Hibiscus Growing Guide

Hibiscus syriacus (rose of Sharon), Hibiscus moscheutos hybrids (hardy hibiscus), Hibiscus rosa-sinensis (Chinese hibiscus)

Crop Rotation Group

Miscellaneous ●

Soil

Moist, well-drained soil enriched with plenty of compost or other organic matter, with a slightly acidic pH.

Position

Full sun.

Frost tolerant

Cold tolerance varies with type of hibiscus being grown. Upright rose of Sharon and hardy hibiscus tolerate cold to -26°C (-15°F), while Chinese hibiscus is a tropical plant that is easily injured by freezing temperatures.

Feeding

Boosting soil fertility results in bigger, better hibiscus flowers. Feed hardy hibiscus in spring after new growth emerges, using a balanced organic fertiliser spread over the root zone of the plant.

Spacing

Single Plants: 1.20m (3' 11") each way (minimum)
Rows: 1.20m (3' 11") with 1.20m (3' 11") row gap (minimum)

Sow and Plant

Hibiscus do not breed true from seed, so it is best to set out purchased plants in spring or early summer. Amend the planting hole with plenty of compost, leaf mould, or other organic matter to help the soil hold moisture. Water regularly, and cover the root zone with an organic mulch to keep the soil lightly moist at all times. Spacing varies with the cultivar grown. Large-flowered hardy hibiscus need 1.2 m (4 feet) between plants. Rose of Sharon is usually grown as a single specimen plant. For containers, one plant is planted per 35 cm (14-inch) pot. In most climates, Chinese hibiscus are grown in containers that can be brought indoors in winter.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

In the last 30 years, plant breeders have made huge advances with hardy hibiscus, native to wetlands of North America. What was once an awkward wild flower is now a showy perennial or sub-shrub producing huge, richly coloured flowers bigger than an outstretched hand. Hardy hibiscus dies back to the ground in winter and regrows in spring. Tall, almost tree-like rose of Sharon (also called althea or common hibiscus) is native to Asia, and is widely grown in temperate climates. Flowers may be white, pink, blue or lavender, depending on cultivar. Adaptable and long-lived, common hibiscus needs little care once established. Popular patio plants, Chinese hibiscus feature exotic flowers in novel colour combinations, but they cannot tolerate freezing weather and must be brought indoors in winter.

Harvesting

Hibiscus flowers are quite short-lived in a vase, but you may want to include the dry seed pods in winter arrangements.

Planting and Harvesting Calendar

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Pests which Affect Hibiscus

Aphids (General)

Slug

Snail