Hardy hibiscus, also called perennial hibiscus and rose mallow, is a woody-based perennial that bears widely funnel-shaped flowers with spreading petals that are white, pink, or crimson. The flowers are borne on erect stems with broadly ovate to lance-shaped mid-green leaves.
The botanical name of the hardy hibiscus is Hibiscus moscheutos. The hardy hibiscus has the largest flowers of all hibiscus, some as large as 12 inches (30cm) across. Plants grow 6 to 8 feet (1.8-2.4m) tall, but there are some cultivars that grow smaller. Hardy hibiscus begins blooming in early summer.
See also How to Grow Rose of Sharon — Hibiscus.
Get to Know Hardy Hibiscus
- Plant type: Perennial
- Growing Zones and range: Zones 5 to 9
- Hardiness: Hardty to -10°F (-23°C); plants die back in winter and reemerge in spring.
- Height and width: 3 to 5 feet (1-1.5m) tall; 3 feet (1m) wide
- Foliage: Entire or shallowly to palmately lobed leaves, sometimes toothed
- Flowers: Large, showy, often funnel-shaped, five-petaled flowers in bold tropical colors borne from spring to autumn.
- Flower colors: Red, pink shades, white
- Bloom time: Late spring to autumn
- Uses: Mass plantings are impressive, hedge, mixed border, smaller cultivars in containers
- Common name: Hardy hibiscus, common rose mallow
- Botanical name: Hibiscus moscheutos
- Family: Malvaceae
- Origin: Widely distributed in tropical and semi-tropical regions
Where to Plant Hardy Hibiscus
- Plant Hibiscus moscheutos in full sun in Zones 2-5; plant in partial shade in hot summer areas in Zones 6-11.
- Grow Hibiscus moscheutos in humus-rich, well-drained soil.
Hardy Hibiscus Uses and Companions
- Use Hibiscus moscheutos in sunny mixed, herbaceous, or shrub border.
- Hibiscus moscheutos is excellent in damp or wet spots in borders; it can be naturalized in a bog garden or along a stream.
- Good garden companions for Hibiscus moscheutos are Aruncus dioicus, Astilbe, Eupatorium, Iris, Lythrum.
When to Plant Hardy Hibiscus
- Set established Hibiscus moscheutos in the garden in spring after all danger of frost has passed.
Planting and Spacing Hardy Hibiscus
- Space Hibiscus moscheutos 3 feet (1m) or more apart.
How to Water and Feed Hardy Hibiscus
- Give hardy hibiscus ample water; thrives in wet, hot conditions.
- Fertilize Hibiscus moscheutos occasionally, every 6 weeks, or work in a 9-month slow-release fertilizer each spring.
Hardy Hibiscus Care
- Mulch around Hibiscus moscheutos to slow soil moisture evaporation.
- Stake tall plants.
Hardy Hibiscus Pests and Diseases
- Hardy Hibiscus moscheutos is prone to rust, fungal leaf spots, bacterial blight, and viruses.
- Hardy Hibiscus moscheutos can be attacked by whiteflies, aphids, mealybugs, and scale insects.
Hardy Hibiscus Propagation
- Sow Hibiscus moscheutos seed in warm soil in spring. Hibiscus seeds germinate in 14 to 21 days at 55° to 64°F (13°-18°C).
- Root greenwood cutting in late spring.
- Layer Hibiscus moscheutos in spring or summer.
Hardy Hibiscus Cultivars to Grow
- Disco Belle strain has 9-inch pink, red, or white flowers on a 30-inch plant.
- Frisbee and Rio Carnival strains are 24 to 30 inches (61-76cm) tall; flowers are 8 to 12 inches wide in red, pink, rose, or white, often with a red eye.
- ‘Blue River’ has pure white flowers; grows to 4 feet (1.2m) tall.
- ‘George Riegel’ has 10-inch ruffled pink flowers with a red eye; grows to 4 feet (1.2m) tall.
- ‘Lord Baltimore’ grows to 6 feet tall and bears deep red 10-inch (25cm) flowers.
- Southern Belle group has very large 10 to 12-inch (25-30cm) red, pink, or white blooms; plants are 3 to 4 feet (1-1.2m) tall.
Other Hibiscus Varieties
- Chinese hibiscus (Hibiscus rosa-sinensis) is hardy to about 30°F (-1.1°C) and reaches 15-feet (4m) tall where hardy.
- Japanese hibiscus (Hibiscus schizopetalus) grows to 9 feet (3m) tall with drooping branches and deeply fringed scarlet or pink flowers.
- Red-leaf hibiscus (Hibiscus acetosella) grown mostly for green or purplish-red leaves; bears dark centered red or yellow flowers; grows to 5 feet (1.5m) tall.
- Roselle (Hibiscus sabdariffa) known as Jamaica flower; annual grows to 5 feet (1.5m) tall; has fleshy red base of yellow flowers; used to make sauce, jelly, cold drinks, and tea.
- Rose of Sharon (Hibiscus syriacus) also called Rose of Sharon, is a deciduous shrub that grows to 12 feet (3.6m) tall; can be trained to a single trunk; single or double flowers look like hollyhocks.