Scarlet rosemallow

Herbaceous perennial

Hibiscus coccineus

Scarlet rosemallow

Also known as: Hibiscus semilobatus, Hibiscus coccineus ‘Texas Star’

A tall herbaceous perennial with deeply cut, hemp-like leaves and huge scarlet, star-shaped flowers in late summer.

  • Full sun, Partial shade
  • 1.5–2.5 m (5–8 ft)
  • 0.6–1 m (2–3 ft)
  • H3 · Zone 8
  • July–September
  • Deciduous

Overview

Also known as scarlet rosemallow or Texas star, this North American marsh-dweller dies back to the ground each winter and sends up tall, upright stems each spring, clothed in narrow, deeply lobed leaves that resemble a maple or even cannabis leaf. From midsummer into early autumn it produces a long succession of huge, single, star-shaped scarlet flowers. It is noticeably less hardy than the related and more commonly grown Hibiscus moscheutos, so in the UK it needs a warm, sheltered, south-facing spot, permanently moist to wet soil, and a thick winter mulch over the crown once it has died down; even then it is a plant for milder gardens rather than a reliable choice everywhere.

At a Glance

Sun Full sun, Partial shade
Height 1.5–2.5 m (5–8 ft)
Spread 0.6–1 m (2–3 ft)
Hardiness H3 · Zone 8
Flowers July–September
Soil Clay, Loam
Moisture Wet
Habit Upright
Water High
Maintenance Moderate

Growing Conditions

Min. Temperature -5°C (23°F)
pH Range 5.5–7
Fertility Fertile

Aspect Suitability

  • South-facing
  • West-facing

Site Tolerance

  • Wet soil

Soil Tolerance

  • Clay
  • Loam
  • Acid
  • Neutral pH

Foliage

Scarlet rosemallow
Scarlet rosemallow
Persistence Deciduous
Colour Green
Leaf shape / texture palmately_lobed
  • Autumn colour
  • Architectural foliage

Foliage interest: May–September

Seasonal Timeline

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Foliage
Fruiting
Propagate
  • Flowering Jul Aug Sep
  • Foliage May Jun Jul Aug Sep
  • Fruiting Sep Oct
  • Propagate Apr May Jun

Maintenance Calendar

  • Apr Remove old winter mulch carefully as late shoots emerge
  • May Divide or plant out once frost risk has passed
  • Jun Keep the root area consistently wet through summer
  • Aug Enjoy the large flowers and their pollinators
  • Nov Cut back after the first hard frost and mulch thickly over the crown

Garden Design

Works well in: Bog, Contemporary, Cottage, Pondside, Tropical, Tropical / Exotic

Give it the warmest, most sheltered spot with reliable moisture - a south-facing pond margin is ideal - and mark its position clearly, since it emerges late and is easily damaged if disturbed while dormant.

Companion planting: Cannas, Persicarias, Late-season perennials

Wildlife Value

  • Bees
  • Butterflies
  • Moths
  • Other pollinators
  • Birds

Safety

No well-established toxicity; ornamental plant not intended for eating.