Hibiscus syriacus

Rose-of-Sharon, Shrub Althea
 

Mature Size, Growth, Longevity

Average mature size of 8-12' tall and 6-10' wide. National champions are over 15' tall and wide. Habit is very erect and upright. A shrub or small tree. Medium growth rate.

Native Range

Species native to China and India. Introduced into cultivation before 1600.

Flower and Fruit Details

Flowers, which attract butterflies, are perfect, 5-petaled, 2-4", borne individually or in pairs, late June, then July-Sept, into October, white, red, purple, pink or violet, varies w/ cultivar. Blooms are produced only on the new growth. Fruits are 3/4", dehiscent, brown capsules, 5-valved, upright, persisting through winter.

Leaf and Bark Features

Deciduous: Leaves are 2-4" long, simple, alternate, with palmate venation, 3-lobed and toothed around the margins, usually glabrous, lustrous on top, dark green to medium green, with a 0.25-1" petiole. Late to leaf out in the spring. Leaves remain green late into the season. Poor yellow fall color. Stems are gray.

Culture and Care

Prefers moist, well-drained sites in hot weather, but adaptable to most soils, including clay. Zones 5-8. Any needed pruning can be done in March, before new growth starts. Avoid extremely wet sites. Likes the heat. Full sun to part shade. Resistant to deer, drought, and walnut juglone toxicity. Susceptible to fungal leaf spots, bacterial leaf spot, blights, canker, rust, Japanese beetle, mining scale, foliar nematodes, white fly, and hibiscus sawfly.

Strengths, Weaknesses, Other Facts

Late-season flowers. 3-season interest: Spring, summer and fall.

Suggested Uses

Good for naturalizing, group or mass plantings, shrub borders, and where late-season woody plant blooms are needed. Also used for screening and hedges.

Taxa and Plants of this Species at BCA

The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.

  • Hibiscus syriacus // Rose-of-Sharon, Shrub Althea ("straight species")
    Shrub.
    Bed 71

  • Hibiscus syriacus 'Aphrodite' // Aphrodite Rose-of-Sharon
    Shrub. This is a mostly sterile cultivar introduced by the U.S. National Arboretum. It often produces fruits, but is mostly sterile. Erect, multi-stemmed habit, and branched low to the ground. 10-12' tall and 8-10' wide. Flowers bloom June-September, are solitary, 4-5" diameter, with short stalks, dark pink in color with a dark red eye spot. Coarse foliage. Definitely hardy to Zone 5.
    -- not currently in our collection --

  • Hibiscus syriacus 'Ardens' // Ardens Rose-of-Sharon
    Shrub. Double, rose-purple flowers.
    Bed 205

  • Hibiscus syriacus 'Diana' // Diana Rose-of-Sharon
    Shrub. This is a mostly sterile cultivar that produces very little fruit, introduced by the U.S. National Arboretum. It is a triploid, with large, pure white flowers, which bloom over a long period of time, and even remain open at night. The leaves are dark green, with a waxy appearance. Could be used to form an allee. Not extremely vigorous, so may need staking to keep it straight upright, especially when grown as a single-stem plant. Bred by Dr. Egolf.
    Bed 167

  • Hibiscus syriacus 'Helene' // Helene Rose-of-Sharon
    Shrub. Flowers mostly white with a reddish-purple blush at base. Few if any fruits. Heavy bloomer in August. Gets 8-10' tall. This is a mostly sterile cultivar introduced by the U.S. National Arboretum. A triploid.
    -- not currently in our collection --

  • Hibiscus syriacus 'Lucy' // Lucy Rose-of-Sharon
    Tree. A vigorous, strong-growing shrub with double, red flowers.
    Bed 165

  • Hibiscus syriacus 'Marina' // Blue Satin® Rose-of-Sharon
    Shrub. Part of the Chiffon and Satin Series. Showy, single, royal-blue flowers with dark red-maroon centers, extending out into the flower veins, giving the flower a starburst appearance. Starts flowering in June, continuing through the summer. A strong grower.
    Bed 213

  • Hibiscus syriacus 'Minerva' // Minerva Rose-of-Sharon
    Shrub. Large, 4-5" diameter, pinkish-lavender flowers are solitary, on short stalks, with a bold, dark red eyespot in the center. Average mature plant size 8-10' tall and 7-9' wide, erect growing, multi stemmed, and low branched. Reliably hardy to Zone 5. This is a mostly sterile cultivar introduced by the U.S. National Arboretum. A heavy bloomer from June through September.
    Bed 66

  • Hibiscus syriacus 'Notwoodone' // Lavender Chiffon™ Rose-of-Sharon
    Shrub. Part of the Chiffon and Satin Series. Large, single, lavender flowers have ruffled lavender centers with maroon-red eyespots, blooming June-September. Five large, outer petals.
    -- not currently in our collection --

  • Hibiscus syriacus 'Notwoodtwo' // White Chiffon™ Rose-of-Sharon
    Shrub. Part of the Chiffon and Satin Series. Single, white flowers with a ruffled center.
    Bed 212

  • Hibiscus syriacus 'Woodbridge' // Woodbridge Rose-of-Sharon
    Shrub. Large, single flowers are rose-pink with a carmine-red "eye" in the center.
    Bed 71