he rose mallow (Hibiscus moscheutos) displays traffic-stopping, saucer-shaped blooms 4 to 7 inches wide-and up to 10 inches on some cultivars-in summer and fall. The delicate, tissue paper-like flowers last just a day, but the plant produces dozens of blooms each season in shades of soft pink, white, bright red, or rose. Some cultivars are compact and stay 4 feet tall, but many grow more than 6 feet and look best in the back of a border. The rose mallow is native to the marshes of eastern United States.

Plant Facts
Common name: Common rose mallow, swamp rose mallow
Botanical name: Hibiscus moscheutos
Plant type: Woody-based perennial
Zones: 5 to 10
Height: To 8 feet, depending on cultivar
Family: Malvaceae

Growing conditions

  • Sun: Full sun
  • Soil: Well-drained soil rich in compost
  • Moisture: Water regularly, especially when the plant is new. Excessive watering may cause root rot.


Care

  • Mulch: Where borderline hardy, mulch heavily in winter.
  • Pruning: Usually not needed
  • Fertilizer: Apply a 10-20-10 fertilizer once in spring.

Propagation

  • Sow seed in springtime when temperatures are 55°F to 64°F.
  • Divide in spring.
  • Layer in spring or summer.

Pests and diseases

  • Rust, fungal leaf spot, stem and root rot, aphids, Japanese beetles, and spider mites are possible.


Garden notes

  • The rose mallow emerges late in spring, so mark its location and be patient-it's a common mistake to dig it up, thinking it didn't survive the winter. Once it emerges, it grows quickly.
  • Hibiscus performs best in long, hot summers.
  • Summer winds can damage flowers, so place in a protected site and stake the plant.
  • Cut back stems in the fall when the plant goes dormant.
  • Mulch heavily in colder zones after the ground is frozen.


Cultivars

  • The Disco Belle Series includes cultivars with red, pink, and white blooms up to 9 inches wide. They grow 2 to 3 feet tall.
  • ‘Fantasia' has lavender 8-inch blooms and reaches 3 feet tall and wide.
  • ‘Southern Belle' has deep rose, red, or white flowers 10 inches across. It grows 4 feet tall.


All in the family

  • The Chinese or tropical hibiscus (Hibiscus rosa-sinensis) is a woody tropical plant. Many small cultivars reaching 3 to 6 feet are popular as container plants.
  • The hollyhock (Alcea rosea) is classed as a perennial or biennial and is hardy in Zones 3 to 9. Depending on the cultivar, it grows as high as 8 feet. A favorite, ‘Chater's Double', has double flowers in a wide range of colors from white to apricot to purple. It grows from 6 to 8 feet tall.
  • Lavatera trimestris is an annual with funnel-shaped pink to white flowers that are attractive cut flowers. It grows 3 to 4 feet tall.
  • Musk mallow (Malva moschata) is a woody perennial bearing pink or white flowers from early summer to fall. It grows 3 feet tall and is hardy in Zones 4 to 8.
  • The Rose of Sharon (Hibiscus syriacus) is a deciduous shrub with small, trumpet-shaped, pink flowers about 2 ½ inches across. It grows 10 feet tall and is hardy in Zones 5 to 9.

Text by Mary Pestel, photo by Amy Sumner