Hibiscus rosa-sinensis ‘Rubrum’ (Red Hibiscus)
Hibiscus ‘Rubrum’ is a tropical, evergreen flowering shrub valued for its large, vibrant red blooms and lush green foliage. It is widely used in gardens and landscapes for its bold colour and continuous flowering in warm climates.
The plant produces glossy, mid to deep green leaves that form a dense, bushy canopy. Throughout the warmer months, and often year-round in tropical conditions, it displays large, trumpet-shaped red flowers that create a strong visual impact.
Key Features
‘Rubrum’ is prized for its intense red flowers and long flowering period. The blooms are typically large and showy, making the plant a standout feature in any garden setting.
It is well suited to hedging, feature planting, and container use, offering both colour and structure.
Its tropical appearance makes it particularly effective in warm-climate landscapes.
Growth Habit and Size
This variety grows as a dense, upright shrub with a rounded form.
It typically reaches 2 to 4 metres in height, with a spread of approximately 1.5 to 3 metres. Growth rate is moderate to fast under favourable conditions.
Care Requirements
Light
Performs best in full sun to partial shade. Full sun promotes stronger flowering and compact growth.
Watering
Requires regular watering to keep the soil consistently moist, especially during active growth.
Water approximately 1–2 times per week, increasing in hot conditions.
Soil
Prefers well-draining, fertile soil enriched with organic matter.
Temperature and Climate
Best suited to tropical and subtropical climates. It thrives in heat and humidity but is sensitive to frost.
In cooler climates, it can be grown in containers and protected during winter.
Maintenance
Moderate maintenance. Regular pruning helps maintain shape and encourages bushier growth and increased flowering.
Fertilise during the growing season with a balanced fertiliser to support flowering.
Remove spent flowers and damaged growth to maintain appearance.
Common Issues
Frost damage can occur in cooler climates.
Yellowing leaves may indicate overwatering, poor drainage, or nutrient deficiencies.
Pests such as aphids, whitefly, or scale may occasionally appear.
Reduced flowering may result from insufficient light or feeding.
Applications
Hibiscus ‘Rubrum’ is suitable for:
Feature planting
Hedging and screening
Tropical-style gardens
Container planting
Courtyards and patios
Coastal and warm-climate landscapes
Its bold flowers make it a focal point in any planting scheme.
Specification and Care Chart
| Attribute |
Details |
| Botanical Name |
Hibiscus rosa-sinensis ‘Rubrum’ |
| Common Name |
Red Hibiscus |
| Plant Type |
Evergreen flowering shrub |
| Mature Height |
2 m to 4 m |
| Growth Habit |
Dense, upright |
| Growth Rate |
Moderate to fast |
| Light Conditions |
Full sun to partial shade |
| Direct Sunlight |
Preferred for flowering |
| Watering Frequency |
Moderate; keep soil consistently moist |
| Soil Type |
Well-draining, fertile |
| Drainage Requirement |
Essential |
| Temperature Range |
Tropical to subtropical |
| Frost Tolerance |
Low |
| Humidity |
High preferred |
| Fertiliser |
Regular feeding during growing season |
| Maintenance Level |
Moderate |
| Toxicity |
Not commonly regarded as toxic |
FAQ – Hibiscus ‘Rubrum’
What colour are the flowers?
Large, vibrant red flowers.
Does it need full sun?
Full sun promotes best flowering, though partial shade is tolerated.
Is it frost tolerant?
No, it is sensitive to frost.
How often should it be watered?
Keep soil consistently moist, typically watering 1–2 times per week.
Can it be used as a hedge?
Yes, it forms a dense flowering hedge.
How big does it grow?
Typically reaches 2 to 4 metres in height.
